COVID-19: Vaccines
Last Updated: July 13, 2022
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Primary Care Operations in the COVID-19 Context
COVID-19 vaccine authorization
Health Canada has authorized a number of COVID-19 vaccines for use in Canada after a thorough and rigorous review of the evidence to ensure the vaccines meet the standards of safety, quality and efficacy for authorization in Canada. Health Canada will continue to monitor the safety of the vaccines after they are available.
Key messages
- Lead by example. Get the COVID-19 vaccine yourself as soon as it is offered to you to protect yourself, your patients, and your community.
- Advise patients to receive the vaccine. Communication by trusted health professionals about the importance of vaccines is the most effective way to counter vaccine hesitancy. Tell your patients you will get or have already received the vaccine.
- Be an educator. Be prepared to answer patient questions and address concerns about the vaccine.
Click on the sections below to get started:
Vaccine rollout in Ontario
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For Ontario’s current vaccination status, see COVID-19 vaccines for Ontario (Government of Ontario).
For up-to-date dose delivery numbers, see Vaccines and treatments for COVID-19: Vaccine rollout (Health Canada).
Update Vaccination eligibility
All individuals aged 6 months and over are eligible for a COVID-19 vaccination in Ontario. The type of vaccine and the dosages may differ depending on your age group.
Vaccinating children
As of 8:00 a.m. on Thursday, July 28, 2022, children aged six months to under five years will be eligible for appointments for the paediatric COVID-19 vaccine. Immunocompromised youth aged 12 to 17 will also become eligible to schedule their second booster dose (fifth dose) if at least six months have passed since their first booster (fourth dose). Children ages 5-11 continue to be eligible for appointments for pediatric COVID-19 vaccines. Appointments can be booked through (Government of Ontario, July 21, 2022):
- COVID-19 vaccination portal
- Provincial Vaccine Contact Centre
- Public health units’ booking systems
- Participating primary care providers and paediatricians
- Participating pharmacies
- Indigenous-led vaccination clinics
Third doses for Ontarians
Ontarians aged 18+ are eligible to receive a third dose of an mRNA vaccine with an interval of 84 days after their second dose (Government of Ontario, January 14, 2022).
As of February 18, 2022, Ontarians ages 12-17 are eligible for booster doses of the Pfizer vaccine 6 months (168 days) after their second dose (Government of Ontario, February 14, 2022). With informed consent, individuals 12-17 years of age may receive a booster dose at a minimum of 3 months (84 days) after completion of a primary COVID-19 vaccine series (MOH, February 17, 2022).
Dosage recommendations for third doses
Either Pfizer or Moderna mRNA vaccines can be used as third doses in Ontario. For individuals ages 18-29 years old, Pfizer is the preferred vaccine for booster doses, however Moderna may be provided due to limited supply. As per NACI, a booster dose of Novavax Nuvaxovid may be offered to individuals without contraindications who are not able or willing to receive an mRNA vaccine (March 24, 2022). A booster dose of a viral vector vaccine should only be offered when all other Health Canada authorized COVID-19 vaccines are contraindicated.
If the Moderna vaccine is being administered as a third dose, a full (100 mcg) dose may be administered to the following populations:
- Residents of long-term care homes, retirement homes or seniors in other congregate living settings
- Adults 70 years of age and older
- Moderately to severely immunocompromised individuals aged 30 years of age and older (for 3rd dose as part of the primary series and for the booster dose)
If the Moderna vaccine is being administered as a third dose, a half (50 mcg) dose should be administered to the following populations:
- All other adults ages 18-70
For all populations receiving the Pfizer vaccine as a third dose, a full (30 mcg) dose is recommended.
Third doses for a primary series
For some moderately to severely immunocompromised populations, a third dose of mRNA vaccine may be administered as part of the primary vaccination series, at a recommended interval of at least 56 days after the second dose. A full dose of either the Pfizer (30 mcg) or Moderna (100 mcg) vaccines should be offered to these populations. Children ages 5-11 should be given the Pediatric Pfizer (10 mcg) vaccine. A list of eligible populations can be found here (MOH, January 13, 2022).
New Second booster dose for Ontarians
As of July 14, 2022 the following Ontarians are eligible to receive a second booster dose of COVID-19 vaccine 5 months after their last booster and 3 months after a COVID-19 infection (Government of Ontario, July 13, 2022).
- Individuals aged 18+
High-risk individuals who should get their second booster dose as soon as possible include (Government of Ontario, July 13, 2022):
- Individuals aged 60+
- First Nation, Inuit and Métis individuals and their non-Indigenous household members aged 18+
- Residents of a long-term care home, retirement home, or Elder Care Lodge and older adults living in other congregate settings that provide assisted-living and health services
- Individuals who are moderately to severely immunocompromised
Ontarians are encouraged to speak with their primary care provider about their decision to get a second booster dose (Government of Ontario, July 13, 2022).
Mixed COVID-19 vaccine schedules
Depending on their first dose, individuals might be able to receive a difference vaccine for the second dose. Whenever possible, individuals should receive their second dose where they received their first dose.
If the first dose was Moderna or Pfizer, the second dose can be Moderna or Pfizer (same vaccine as first dose unless unavailable).
How to book
Eligible individuals can book an appointment through the provincial booking system or by contacting a participating pharmacy offering Moderna or Pfizer.
If the first does was AstraZeneca, the second dose can be AstraZeneca, Moderna or Pfizer.
How to book
Eligible individuals can book an appointment through the provincial booking system (for Moderna and Pfizer only) or by contacting a participating pharmacy offering their vaccine of choice.
See How to book a COVID-19 vaccine appointment (Government of Ontario) for more information on how to schedule a first or second dose appointment.
Homebound individuals
Homebound Patients/Clients have medical, physical, cognitive, or psychosocial needs/conditions that inhibits them from visiting a local clinic, pharmacy, or their primary care provider to receive their COVID-19 Vaccination. Furthermore, transportation and other strategies to remedy the access difficulties have been considered but are not available or not appropriate in the person’s circumstances. PHUs and FHTs across Ontario are developing ways to reach homebound patients for vaccination. Contact your local PHU for details.
Click your public health unit below for up-to-date information regarding their current regional vaccination status and vaccination plan:
Are AstraZeneca and Janssen (Johnson & Johnson) being distributed in Ontario?
As of May 11, 2021, Ontario has paused the administration of first doses of AstraZeneca vaccine. Ontarians who had a 1st dose of AstraZeneca can get AstraZeneca, Moderna, or Pfizer for their second dose, at least 8 weeks after their first dose. (Government of Ontario, August 17, 2021; Government of Ontario, May 11, 2021).
Vaccination in primary care
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Vaccination in primary care
Offering vaccinations in primary care
- If you are interested in offering vaccinations, contact your public health unit or see the list of Public Health Contacts for Primary Care to learn about the process in your area.
- Review the OMA’s Deciding whether to provide the COVID-19 vaccine in your practice (OMA, April 2021) [login required] resource to determine your clinic’s physical, administrative and financial capacity to offer vaccination.
- If you do have the capacity to offer vaccinations, it will be up to your clinic to determine which format you want to use (regular appointments, specific vaccination clinic times, drive-through clinic, etc). Resources:
- COVID-19 Vaccination Clinic Workflow Data and EMR Tips & Tricks. Learn from the experience of Windsor FHT, Hamilton FHT, Upper Grand FHT, London FHT and many more on running vaccination clinics (AFHTO, 2021).
- COVID-19 Vaccination Mass Client Upload Workflow (Excel, EMR & COVaxON) for information on extracting data from your EMR (Telus PSS and Accuron) and uploading to COVaxON (AFTHO, 2021).
- Primary Care COVID-19 Immunization Toolkit for information on identifying patients, planning and running clinics, and more (Primary Care Innovation Support Unit, 2021)
- Guide to Providing COVID-19 Vaccines Through Your Practice (OMA). A high level view of the steps to COVID-19 immunization in Ontario, including learnings from the pilots.
Additional resources
- Consider sharing Partnering with primary care for local COVID-19 vaccine rollout in Ontario: A practical guide, a resource created by AHC, AFHTO, IPHCC, SGFP, NPLCA, OCFP, Alpha, COMOH, CEP, NPAO, OHA, OMA, RNAO and endorsed by the Provincial Primary Care Advisory Table.
- Review and implement Engaging Indigenous Communities with COVID Vaccine Implementation (IPHCC) as appropriate to your practice area.
- View the Wise Practices for COVID-19 Vaccinators webinar. Learn how to design and deliver high-quality, culturally safe vaccination services to First Nations, Inuit, and Métis people receiving their vaccinations through mainstream health services both on-reserve and in urban settings.
- If in the GTA, review the Toronto Region Vaccine Human Resource Strategy, “Vaccine Clinic Playbook: Models, Roles, Sourcing and Training”.
- If an Ocean user, consider leveraging Ocean engagement tools to support your COVID-19 vaccination clinic efforts.
Identifying vaccine-eligible patients
Rationale and key messages
- Even if you’re not vaccinating, the role of primary care providers in identifying and contacting eligible patients is crucial in ensuring patients don’t fall through the cracks.
- Well-constructed communications about vaccines can help build trust between you and your patients.
- Most patients who are vaccine hesitant report that their primary care provider’s recommendation is of high value when making the decision to be vaccinated.
Communication strategy
- Determine how you plan on contacting your patients (email/secure messaging, text/sms, phone, mail). If feasible, consider at least a two-pronged approach. Using a mass email/secure messaging or text/sms campaign requires minimal effort and can yield high results, allowing you to engaging patients that are less accessible.
Identifying eligible populations
- Consider contacting your patients who have yet to be vaccinated to help them understand the benefits of receiving the COVID-19 vaccine. The COVaxON Aggregate Primary Care Vaccination Report identifies your rostered patients that have received a COVID-19 vaccine (Ontario Health). To identify eligible patients, use your ONE ID to log in here.
- See Provincial vaccine rollout to identify which patients are eligible in your local PHU.
Paper-based clinics
- You can use your billing system to identify patients.
- See: Use your Billing System to Identify Patients, (covidtoolkit.ca).
- Once you have the results, you will need to import the list into your email system.
OntarioMD is offering training for primary care practices that have been identified by their local public health unit to administer COVID19 vaccinations.
A network of 60+ clinicians who offer free, direct support to assist healthcare providers in selecting and implementing health technologies that will best serve their unique needs.
Provincially funded change management services to support primary care providers with the adoption of virtual care, with the goal of improving timely access to primary care and ensuring that all patients in the region are getting the care they need, when they need it.
EMR-based clinics
Telus PS
Accuro
Tips for running reports
- Before running your search review the report format to ensure that the following information will be included in your results to support your communication strategy: home phone number, cell/mobile phone number and email address.
- If you have 3rd party/EMR add-on that allows you to send communications to patients directly from the EMR, you may have the option to email “all” after running your search(es).
- If you don’t have a 3rd party/Telus PSS Add-on, export your search results into your preferred form (i.e. csv for excel/pdf for printing). For more information on how to export your search results see your EMR User guide. Administrative staff may be able to assist in this step.
Conduct patient outreach
- Use the Local vaccine rollout details table to identify which booking systems are in use by your local PHU(s) and capture this information for your communications, website, etc.
- Email/secure messaging: Filter your eligibility search results to identify patients with an email address. Customize this mass communication email template with information specific to your region. See: Vaccination Email Template (CEP, 2021).
- BCC: If you are using a clinic email and not an 3rd party/EMR add-on, ensure patient privacy by making sure to email all patients under the “bcc.”
- Text/SMS: Filter your eligibility search results to identify patients with a mobile number. Consider using mass texting services to connect with patients for information about vaccine appointments and link to local PHU. Use the Local vaccine rollout details table to identify your local PHU.
- Sample text: “COVID-19 Vaccine Update: We are currently not booking vaccinations. Check [local PHU page] for up-to-date information on local vaccination plans. Please avoid calling in an attempt to schedule vaccinations at this time.”
- Phone: Filter your eligibility search results to identify patients you plan to call (i.e. those not contacted via email/secure messaging or text/sms). Use the Local vaccine rollout details table to identify your local PHU.
Educate patients and track vaccine hesitancy
- For patients that don’t take action, use the PRoTCT framework (English and French) to frame conversations exploring their reticence, to build trust and encourage them to take the vaccine.
- To alleviate concerns about the injection itself, use the CARD system (Comfort, Ask, Relax, Distract) to support conversations. See: Preparing for your COVID-19 vaccine: A guide for health care workers (Immunize.ca).
- Share vaccine resources for Black communities: Toronto Black Covid-19 Information portal. Twitter: @TorontoTask. Published by the Black Scientists’ Task Force on Vaccine Equity.
- Share vaccine resources for Indigenous communities: share the Maad’ookiing Mshkiki — Sharing Medicine information portal. Developed by The Centre for Wise Practices in Indigenous Health (CWP-IH) in partnership with Indigenous Primary Health Care Council (IPHCC), Anishnawbe Health Toronto (AHT) and The University Health Network, Indigenous Health (UHN) and Shkaabe Makwa (CAMH)).
- Track patients who decline the vaccine and revisit their decision in subsequent appointments. People may change their mind and decide to vaccinate at a later time or with a newly available vaccine, so it is important to revisit this discussion over time with your patients.
Billing
- You may be able to bill for this work. See: OHIP Info Bulletin (March 2021).
- COVID-19 Billing Summary (OMA). Updated to reflect clarifications that address member questions and now includes two flowchart decision trees to guide members through the use of COVID-19 billing codes.
Educate yourself about the vaccines and common questions patients have
- See Types of COVID-19 vaccines to learn about different types of vaccines, their mechanisms of action, advantages and disadvantages.
- To learn about each approved vaccine, including clinical trial, vaccine ingredients, contraindications, and point-of-care guidance, see:
- See Vaccine confidence for answers to common questions about the vaccines, and resources and supports for learning about the reasons for vaccine hesitancy and how to have productive conversations to improve vaccine confidence.
- Work through the training module COVID-19 vaccination in Canada: an educational series for primary care professionals (DFCM/OCFP, 2021).
- For information on identifying and informing eligible patients, planning and running your immunization clinic and following up with patients post-vaccination, see Primary Care COVID-19 Immunization Toolkit (University of British Columbia, 2021).
- CMPA has developed 2 resources on medical-legal questions surrounding vaccination. See COVID-19 vaccination: Medical-legal FAQ (CMPA, 2021) and How to address vaccine hesitancy and refusal by patients or their legal guardians (CMPA, 2020).
Vaccination logistics
COVaxON
OntarioMD is providing additional training and onboarding on COVaxON (the vaccine registration system) for clinical providers, initially focused on those who are directly involved in vaccine pilots, including support for technical questions that arise throughout the process. You can register for training at OntarioMD. A Clinical Workflow Training recording is also available.
See OntarioMD deck on COVaxON, which provides a high-level overview of the system and supports.
Delivery
- For information on preparation, administration, storage, stability and disposal, see Vaccine administration.
- Provide patients with an after-care sheet with information about their vaccine, 2nd dose (if needed) and what to expect in the days after receiving the vaccine.
- For after-care documents in a variety of languages please click here.
Tracking patient vaccinations
Primary care providers using an OntarioMD-certified EMR can securely receive reports on their patients who have been vaccinated at any vaccination location including pharmacies, mass vaccination clinics or in hospital or specialty clinic through the Health Report Manager (HRM) service. HRM® electronically delivers text-based Medical Record reports from sending facilities directly into patients’ chart within the clinician’s EMR.
If you already receive reports through HRM®, you will receive the reports automatically.
If you are not already receiving reports through HRM® but wish to do so, you can gain access through the following steps:
- If you use an OntarioMD-certified EMR contact OntarioMD at support@ontariomd.com
- Your OntarioMD Practice Advisor will schedule a meeting with you at which time you will review the HRM® Welcome Package.
- Review the Welcome Package for HRM® with the OntarioMD Practice Advisor.
- Sign the Subscription Agreement and a User Agreement for each clinician who will be using HRM®.
- OntarioMD will then work with you and your vendor to connect to HRM®.
For answers to common questions, see the OntarioMD COVaxON – HRM FAQ
Aggregate Primary Care Vaccination Report
Ontario Health has developed a new report to help primary care providers identify patients in their panels that have received a COVID-19 vaccine. Available by mid-July, the Aggregate Primary Care Vaccination Report will be:
- Available for providers with OneIDs, practicing as part of a patient enrollment model (FHO, FHG, FHN, CCM)
- Accessible through an online platform similar to the Screening Activity Report.
- Updated monthly and will include information on vaccine type as well as date(s) received.
OH recommends providers also use the tool proactively to identify and contact patients who are not yet vaccinated and may need assistance scheduling their appointments.
Though the report is not yet available, there are steps providers can take in preparation.
- Log in to your ONE® ID account here: https://oneid.ehealthontario.ca/login
- If you have forgotten your password, click the “Forgot Password” link on the login screen to reset your password.
- If you do not have a ONE® ID account, physicians need to log in to the CPSO Members Portal to self-register for a ONE® ID account here: https://my.cpso.on.ca/
For instructions on completing your ONE® ID self-registration, refer to the ONE® ID CPSO RegistrationGuide. If you require further assistance with accessing your ONE® ID account, please call the Ontario Health Digital Support Desk at 1-866-250-1554 or email OH-DS_servicedesk@ontariohealth.ca for assistance. If you have any questions about the upcoming Aggregate Primary Care Vaccination Report, please email OH-HQO_PrimaryCare@ontariohealth.ca.
Resources to Support the Aggregate Primary Care Vaccination Report
- Ontario MD – EMR-eReport Patient Vaccination Reconciliation Toolkit: These tools and toolkits were designed to be used with the Aggregate Primary Care Vaccination Report and includes supports for different EMR systems.
- eHealth Centre of Excellence – COVID-19 Vaccination Supports for Primary Care: The eCE Automates team at the eHealth Centre of Excellence has launched a bot process to help primary care clinicians document their patients’ COVID-19 vaccinations within their electronic medical records (EMRs).
- Ontario Medical Association – Accessing the COVaxON Aggregate Primary Care Vaccination Report:
- Frequently asked questions about the Aggregate Primary Care Vaccination Report.
Vaccine exemptions
The list of conditions and AEFIs that qualify for vaccine exemption is limited. It will be extremely rare that patients qualify for vaccine exemption.
When the patient making the request does not have a medical condition that warrants an exemption, clearly and sensitively explain to the patient that you cannot provide them with a note or form and give the reasons why (CPSO).
Broadly speaking, the conditions or adverse events listed below will qualify for medical exemption only if all the following conditions are met:
- The condition or event is documented by a specialist
- Discussion with a relevant specialist has occurred on potential options for immunization with the same or alternative COVID-19 vaccine
- The specialist has determined that the individual is unable to receive any COVID-19 vaccine.
For more details on management for specific conditions, see Medical Exemptions to COVID-19 Vaccination (MOH).
Conditions/Adverse events that may qualify for exemption
- Severe allergic reaction or anaphylaxis to a component of a COVID-19 vaccine
- Myocarditis prior to initiating an mRNA COVID-19 vaccine series (individuals aged 12-17 years)
- History of capillary leak syndrome (CLS)
- History of cerebral venous sinus thrombosis (CVST) with thrombocytopenia
- History of heparin-induced thrombocytopenia (HIT)
- History of major venous and/or arterial thrombosis with thrombocytopenia following any vaccine
- Severe allergic reaction or anaphylaxis following a COVID-19 vaccine
- Thrombosis with thrombocytopenia syndrome (TTS)/VITT4 following the AstraZeneca vaccine
- Myocarditis or Pericarditis following an mRNA COVID-19 vaccine
- Serious adverse event following COVID-19 immunization (e.g. results in hospitalization, persistent or significant disability/incapacity)
- Actively receiving monoclonal antibody therapy OR convalescent plasma therapy for the treatment or prevention of COVID-19 (time-limited medical exemption while they are actively receiving therapy)
Writing exemption notes
For patients who qualify for a medical exemption, notes must specify:
- The reason they cannot be vaccinated against COVID-19
- Whether this exemption is permanent or time-limited
Vaccine administration
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Administration Guidance
Patients with previous COVID-19 infections
Timing of other vaccinations
For patients partially or fully vaccinated outside of Ontario/Canada
Adverse events
COVID-19 vaccine administration errors and deviations
Vaccine specific preparation and storage / stability guidance
Disposal guidance
Vaccine details at a glance
Scroll (left-right) for details
Administration guidance for all vaccines
- As with all injectable vaccines, appropriate medical treatment and supervision should always be readily available in case of a rare anaphylactic event following the administration of these vaccines.
- The vaccines are administered through an intramuscular (IM) injection into the upper arm.
- Similar to other immunizations, ask patients to wait for 15 minutes following administration in order to monitor for adverse events, such as anaphylaxis.
- For patients with a history of anaphylaxis not related to vaccines or injectable medications (e.g., allergies to food, pets), a waiting period of 30 minutes is recommended.
- Remind patients to continue to practice recommended public health measures for prevention and control of SARS-CoV-2 infection and transmission regardless of receipt of COVID-19 vaccine, due to insufficient evidence on the duration of protection and effectiveness of COVID-19 vaccines in preventing asymptomatic infection and reducing transmission of SARS-CoV-2 (NACI, March 1, 2021).
- People with previous SARS-CoV-2 infection may continue to be offered a complete vaccine series at the recommended intervals, regardless of the severity of their previous infection. (NACI, October 22, 2021)
Timing of doses
- The recommended interval between doses is 8 weeks (56 days) for Pfizer and Moderna vaccines and at least 8 weeks (56 days) for the AstraZeneca vaccine (MOH, November 15, 2021). The recommended interval for the Pediatric Pfizer vaccine is also 8 weeks (56 days) for children ages 5-11 (MOH, November 22, 2021).
- For most vaccines, interruption of a vaccine series does not require restarting the series as delays between doses do not result in a reduction in final antibody concentrations for most multi-dose products.
- However, maximum protection may not be attained until the complete vaccine series has been administered.
For patients with previous COVID-19 infections
NACI has released the following guidance for different populations of patients with previous COVID-19 infections (NACI, February 4, 2022):
- Individuals ages 5 and older (not moderately or severely immunocompromised and no history of MIS-C)
- Receive vaccine dose 8 weeks after symptom onset (or positive test)
- Individuals ages 5 and over (moderately or severely immunocompromised and no history of MIS-C)
- Receive vaccine dose 4 to 8 weeks after symptom onset or positive test
- Individuals ages 5 and over with a previous history of MIS-C
- Receive vaccine dose when clinical recovery has been achieved or ≥90 days since the onset of MIS-C, whichever is longer
- For patients ages 12 and over who are eligible for a booster dose and recently have had a COVID-19 infection are recommended to receive their booster dose 3 months after symptom onset (or positive test), and for patients 12-17 years old, provided it is at least 6 months from completing the primary series.
Timing of other vaccinations
NACI recommends that COVID-19 vaccines may be given at the same time as, or any time before or after, other vaccines in patients ages 12 and over. This includes live, non-live, adjuvanted or unadjuvanted vaccines. As a precautionary measure, the COVID-19 vaccine is not recommended to be given within 14 days of other vaccines in children ages 5-11 (Health Canada, November 19, 2021).
For patients partially or fully vaccinated outside of Ontario/Canada
Providers should recommend the following to patients with different vaccine statuses (MOH, February 1, 2022):
One additional dose of an mRNA vaccine
Recommend to patients who:
- received a complete one or two-dose series of a COVID-19 vaccine that is not authorized for use by Health Canada
- received an incomplete series of a COVID-19 vaccine that is not authorized for use by Health Canada
- received the first dose of a two-dose Health Canada authorized COVID-19 vaccine series outside of Ontario or Canada
A full series of vaccines
Recommend to patients who:
- received an unknown or unrecognized vaccine
- received vaccines but have no proof of immunization (should first be advised to contact clinic location/health care provider or immunizer, etc.)
Adverse events
If a patient experiences a side effect following immunization, such as hives, swelling of the mouth and throat, trouble breathing, hoarseness, wheezing, high fever (over 40oC), convulsions, seizures, or other serious reactions.
- Complete the Adverse Events Following Immunization (AEFI) Form appropriate for your province/territory and send it to your local Health Unit. Health Canada and the Public Health Agency of Canada will monitor for any adverse events that may develop after immunization. This monitoring is done in collaboration with the provinces/territories and the manufacturer.
- See PHO’s short AEFI fact sheet for more details (PHO, 2020).
- The Brighton Collaboration has developed a list of Adverse Events of Special Interest.
Individuals who received a complete series of Health Canada approved vaccines outside of Ontario/Canada follow the same guidance for booster doses as those vaccinated within Ontario/Canada. Individuals, ages 18+, with proof of immunization of three doses (at the appropriate interval) of non-Health Canada authorized vaccine may receive a booster dose of approved vaccine 84 days + after their last dose (MOH, February 1, 2022)
COVID-19 Vaccine administration errors and deviations
Following the identification of an inadvertent vaccine administration error or deviation, healthcare providers should (MOH, June 2021):
- Inform the recipient of the vaccine administration error/deviation as soon as possible after it has been identified.
- Inform the recipient of any implications/recommendations for future doses, and the possibility for local or systemic adverse events (if applicable and as known).
- If an inadvertent vaccine administration error or deviation results in an AEFI, complete Ontario’s AEFI reporting form, including details of the error or deviation and submit to your local PHU.
- Determine how the vaccine administration error or deviation occurred and promptly implement strategies to prevent it from happening again.
- Serologic testing to assess vaccine-induced immunity following COVID-19 vaccine errors or deviations is generally not recommended to guide management decisions. Providers are encouraged to contact their local PHU or PHO for advice if they are considering using serology to investigate an error or deviation.
- Document in clinical notes field in COVaxON
Vaccine specific preparation and storage / stability guidance
Pfizer-BioNTech – Ages 12+
Ages 12 and Older (Purple Cap Vials)
- The Pfizer-BioNTech COVID-19 vaccine multiple dose vial contains a frozen suspension and must be thawed and diluted prior to administration.
- Vials may be thawed in the refrigerator (2°C to 8°C), or at room temperature (up to 25°C).
- Prior to dilution, the thawed suspension may contain white to off-white opaque amorphous particles. DO NOT SHAKE. Before dilution, the vial should be gently inverted ten times to mix.
- Sterile 0.9% Sodium Chloride Injection, USP is not packaged with the vaccine and must be sourced separately. DO NOT USE BACTERIOSTATIC STERILE 0.9% SODIUM CHLORIDE INJECTION OR ANY OTHER DILUENT.
- The contents of the vial must be diluted with 1.8 mL of sterile 0.9% Sodium Chloride Injection, USP to form the Pfizer-BioNTech COVID-19 Vaccine. The vial should be gently inverted ten times to mix.
- After dilution, one vial contains 6 doses of 0.3 mL. Vial labels and cartons may state that a vial contains 5 doses of 0.3 mL. Health Canada has approved a label change rendering the 5 dose statement outdated.
- Low dead-volume syringes and/or needles can be used to extract 6 doses from a single vial. If standard syringes and needles are used, there may not be sufficient volume to extract a 6th dose from a single vial.
- After dilution, the vaccine will be an off-white suspension. Inspect vials to confirm there are no particulates and no discolouration is observed.
- Visually inspect each dose in the dosing syringe prior to administration. If the visual inspection fails, do not administer the vaccine.
- Time and date of dilution must be recorded on the vial label. Any unused vaccine must be discarded 6 hours after dilution.
- Vaccine must be stored between 20°C and 25°C.
- Strict adherence to aseptic techniques must be followed.
Ages 12 and Older (Purple Cap Vials)
Frozen vials prior to use
- Vials must be kept frozen between -80°C to -60°C (-112°F to -76°F) or between -25°C to -15°C (for up to 2 weeks).
- Vials stored at -25°C to -15°C for up to 2 weeks may be returned one time to the recommended storage condition of -80°C to -60°C. Total cumulative time the vials are stored at -25°C to -15°C should be tracked and should not exceed 2 weeks.
- If an ultra-low temperature freezer is not available, the thermal container in which the Pfizer-BioNTech COVID-19 Vaccine arrives may be used as temporary storage when consistently refilled to the top of the container with dry ice. Refer to the re-icing guidelines packed in the original thermal container for instructions regarding the use of the thermal container for temporary storage. The thermal container maintains a temperature range of -90°C to -60°C (-130°F to -76°F). Storage within this temperature range is not considered an excursion from the recommended storage condition.
Thawed vials prior to dilution
- Prior to dilution, vials may be thawed and stored in the refrigerator [2°C to 8°C (35°F to 46°F)]. A carton of 25 vials or 195 vials may take up to 2 or 3 hours to thaw in the refrigerator, respectively, whereas a fewer number of vials will thaw faster. Vials may be stored in the refrigerator for up to one month if thawed in refrigerator.
- Frozen vials may also be thawed at room temperature [up to 25°C (77°F)]. Prior to dilution, vials may be stored at room temperature for no more than 2 hours.
- During storage, minimize exposure to room light, and avoid exposure to direct sunlight and ultraviolet light.
- Thawed vials can be handled in room light conditions. Do not refreeze thawed vials.
Vials after dilution
- After dilution, vials must be stored between 2°C to 25°C (35°F to 77°F) and used within 6 hours from the time of dilution.
- Any vaccine remaining in vials must be discarded after 6 hours.
- After dilution, the vaccine vials can be handled in room light conditions.
- Do not freeze. If the vaccine is frozen, it must be discarded.
- Use the product before the expiration date on the vial label.
Pfizer-BioNTech – Ages 5-11
Ages 5-11 (Orange Cap Vials)
- The Pfizer-BioNTech COVID-19 vaccine multiple dose vial contains a frozen suspension and must be thawed and diluted prior to administration.
- Vials may be thawed in the refrigerator (2°C to 8°C), or at room temperature (up to 25°C).
- Prior to dilution, the thawed suspension may contain opaque amorphous particles. DO NOT SHAKE. Before dilution, the vial should be gently inverted ten times to mix.
- Sterile 0.9% Sodium Chloride Injection, USP is not packaged with the vaccine and must be sourced separately. DO NOT USE BACTERIOSTATIC STERILE 0.9% SODIUM CHLORIDE INJECTION OR ANY OTHER DILUENT.
- The contents of the vial must be diluted with 1.3 mL of sterile 0.9% Sodium Chloride Injection, USP to form the Pfizer-BioNTech COVID-19 Vaccine. The vial should be gently inverted ten times to mix.
- After dilution, one vial contains 10 doses of 0.2 mL.
- Low dead-volume syringes and/or needles can be used to extract 10 doses from a single vial. If standard syringes and needles are used, there may not be sufficient volume to extract 10 doses from a single vial. If the amount of vaccine remaining in the vial cannot provide a full dose of 0.2 mL, discard the vial and any excess volume.
- After dilution, the vaccine will be an off-white suspension. Inspect vials to confirm there are no particulates and no discolouration is observed.
- Visually inspect each dose in the dosing syringe prior to administration. If the visual inspection fails, do not administer the vaccine.
- Time and date of dilution must be recorded on the vial label. Any unused vaccine must be discarded 12 hours after dilution.
- Vaccine must be stored between 2°C and 25°C.
- Strict adherence to aseptic techniques must be followed.
Ages 5-11 (Orange Cap Vials)
Vial storage prior to use
- Vials may be kept frozen between -90°C to -60°C (-130°F to -76°F) or may be transferred to the refrigerator between 2°C to 8°C, thawed and stored for up to 10 weeks.
- Do not store vials at -25°C to -15°C.
- If vials are received at 2°C to 8°C, they should be stored at 2°C to 8°C. Check that the carton has been updated to reflect the 10-week refrigerated expiry date.
- Vaccines should not be used after 6 months from the date of manufacture.
- Once vials are thawed, do not refreeze.
Vial storage during use
- If the vial is not already thawed at 2°C to 8°C, thaw at room temperature [up to 25°C (77°F)] for 30 minutes.
- Prior to dilution, vials may be stored at temperatures up to 25°C (77°F) for a total of 12 hours.
- After dilution the vials should be stored at 2°C to 25°C (35°F to 77°F).
- Vials should be discarded 12 hours after dilution
- If the vial labels and cartons state that a vial should be discarded 6 hours after dilution, information in the Product Monograph supersedes the number of hours printed on vial labels and cartons.
Moderna
5 mL multidose vials (red cap)
- The Moderna COVID-19 Vaccine multiple-dose vial contains a frozen suspension and must be thawed prior to administration.
- Thaw the required number of vials in refrigerated conditions between 2° to 8°C for 2 hours and 30 minutes. After thawing, let the vial stand at room temperature for 15 minutes before administering. Alternatively, thaw at room temperature between 15° to 25°C for 1 hour.
- Do not refreeze.
- Swirl vial gently after thawing and between each withdrawal. Do not shake.
- The Moderna vaccine is a white to off-white dispersion. It may contain white or translucent product-related particulates.
- Visually inspect the vials for foreign particulate matter and/or discoloration prior to administration. If either of these conditions exists, do not administer the vaccine.
- A needle length of ≥1 inch should be used to administer the vaccine intramuscularly as shorter needles may be of insufficient length to penetrate muscle tissue in some adults.
- Using aseptic technique, cleanse the vial stopper with a single-use antiseptic swab.
- Use a new sterile needle and syringe for each vaccine withdrawal and injection.
- Pierce the stopper at a different site each time. Do not puncture the vial more than 20 times.
- Use the dose in the syringe as soon as possible. The vial must be used within 24 hours after first puncture.
- The Moderna COVID-19 Vaccine must not be reconstituted, mixed with other medicinal products, or diluted.
2.5 mL multidose vials (royal blue cap)
- The Moderna COVID-19 Vaccine multiple-dose vial contains a frozen suspension and must be thawed prior to administration.
- Thaw the required number of vials in refrigerated conditions between 2° to 8°C for 2 hours. After thawing, let the vial stand at room temperature for 15 minutes before administering. Alternatively, thaw at room temperature between 15° to 25°C for 45 minutes.
- Do not refreeze.
- Swirl vial gently after thawing and between each withdrawal. Do not shake.
- The Moderna vaccine is a white to off-white dispersion. It may contain white or translucent product-related particulates.
- Visually inspect the vials for foreign particulate matter and/or discoloration prior to administration. If either of these conditions exists, do not administer the vaccine.
- A needle length of ≥1 inch should be used to administer the vaccine intramuscularly as shorter needles may be of insufficient length to penetrate muscle tissue in some adults.
- Using aseptic technique, cleanse the vial stopper with a single-use antiseptic swab.
- Use a new sterile needle and syringe for each vaccine withdrawal and injection.
- Pierce the stopper at a different site each time. Do not puncture the vial more than 10 times.
Frozen vials prior to use
- The Moderna COVID-19 vaccine should be stored at temperatures of -50ºC to -15ºC.
Unpunctured vials
- Unpunctured vials can be stored refrigerated between 2° to 8°C for up to 30 days prior to first use.
- Unpunctured vials may be stored between 8° to 25°C (46° to 77°F) for up to 24 hours.
- Do not refreeze thawed vials.
- If vials were transported in a liquid state at 2° to 8°C (for up to 12 hours), vials should not be refrozen and should be stored at 2° to 8°C until use.
Punctured vials
- Once punctured, the vial can be stored at room temperature or refrigerated
- Punctured vials must be discarded after 24 hours. Do not refreeze.
Janssen
- Prior to use, Janssen COVID-19 vaccine may be stored and/or transported at a refrigerated temperature of 2°C to 8°C until expiry date.
- While it is not a recommended storage or shipping temperature range, Janssen COVID-19 Vaccine is stable for a total of 12 hours at 9°C to 25°C.
- The vaccine must be stored in the original package in order to protect from light. Do not freeze.
- Do not discard unpunctured vials prior to the expiration date. As the expiration date approaches, check to see if the expiration date has been extended (see Product Monograph, including patient medication information: Janssen COVID-19 Vaccine for details).
- Before administering a dose of vaccine, carefully mix the contents of the multi-dose vial by swirling gently in an upright position for 10 seconds. Do not shake.
- Visually inspect the Janssen COVID-19 vaccine for particulate matter and discolouration prior to administration. The vaccine is a colourless to slightly yellow, clear to very opalescent suspension. The vial should be inspected visually for cracks or any abnormalities. If any of these should exist, do not administer the vaccine.
- The Janssen vaccine is one dose of 0.5 mL is administered intramuscularly in the deltoid muscle by syringe.
- A needle length of ≥1 inch should be used as needles <1 inch may be of insufficient length.
- After first puncturing the vial:
- Janssen COVID-19 vaccine can be held at 2°C to 8°C for up to 6 hours
- Or at room temperature (maximum 25°C) for up to 3 hours
- The vaccine must be discarded if not used within this time
- The vial must be kept in the original package in order to protect from light during storage. Do not freeze.
- Janssen COVID-19 vaccine must not be reconstituted, mixed with other medicinal products, or diluted.
Unpunctured Vials
- Janssen COVID-19 vaccine should be stored in a refrigerator (2 to 8ºC) in the outer carton to protect from light. Do not freeze the vial.
- The vaccine must be used by the expiration date. The method of determining the expiration date differs based on the type of label included (i.e., Orange label vs White label). For details, see pages 13-14 of the Product Monograph, including patient medication information: Janssen COVID-19 Vaccine.
Punctured Vials
- Once punctured, the vial can be stored:
- at 2°C to 8°C for up to 6 hours
- at room temperature (maximum 25°C) for up to 3 hours
- Discard if the vaccine is not used within this time.
AstraZeneca
- Each vial contains at least the number of doses stated. When low dead volume syringes and/or needles are used, the amount remaining in the vial may be sufficient for an additional dose.
- Where a full 0.5 mL dose cannot be extracted, the remaining volume should be discarded. Do not pool excess vaccine from multiple vials.
- The AstraZeneca COVID-19 vaccine does not contain any preservative.
- The vaccine can be stored in a refrigerator (2 to 8ºC). Do not freeze the vaccine.
- After first opening, use the vial within:
- 6 hours when stored at room temperature (up to 30ºC), or
- 48 hours when stored in a refrigerator (2 to 8ºC ).
- The vial can be re-refrigerated, but the cumulative storage time at room temperature must not exceed 6 hours. The vial must be discarded if the total cumulative storage time after opening exceeds 48 hours. The vaccine must be used by the expiration date on the label.
- AstraZeneca COVID-19 Vaccine must not be reconstituted, mixed with other medicinal products, or diluted.
Unpunctured Vials
- The AstraZeneca COVID-19 vaccine should be stored in a refrigerator (2 to 8ºC). Do not freeze the vial. Use the product before the expiration date on the vial label.
Punctured Vials
- Once punctured, the vial can be stored:
- at room temperature (up to 30ºC) for 6 hours
- in a refrigerator (2 to 8ºC ) for 48 hours
- The vial can be re-refrigerated but the cumulative storage time at room temperature must not exceed 6 hours.
- The vial must be discarded if total cumulative storage time after opening exceeds 48 hours.
- The vaccine must be used by the expiration date on the label.
Novavax
- Novavax must not be reconstituted, mixed with other medicinal products, or diluted.
- The vaccine is colourless to slightly yellow, clear to mildly opalescent suspension, free of particles.
- Gently swirl the multidose vial before and in between each dose withdrawal. Do not shake.
- Visually inspect the contents of the vial for visible particulate matter and/or discolouration prior to administration. Visually inspect the vial for cracks or any abnormalities, such as evidence of tampering. If the visual inspection fails, do not administer the vaccine.
- Use a sterile needle and sterile syringe to administer the vaccine through intramuscular injection. Do not inject intravascularly, subcutaneously, or intradermally.
- The Novavax COVID-19 vaccine must not be mixed with any other vaccines or medicinal products in the same syringe.
- Do not pool excess vaccine from multiple vials.
- Time and date of discard must be recorded on the vial label. Any unused vaccine must be discarded 6 hours after vial puncture.
- Do not freeze the vials.
- Keep the vials in the outer carton to protect from light.
Storage prior to use
- Store unopened Novavax vials in the refrigerator between 2° to 8°C (36° to 46°F) for a maximum of 9 months.
Storage of Punctured vials
- Store the opened vial between 2°C to 25°C for up to 6 hours after first puncture.
- Novavax does not contain a preservative.
Medicago Covifenz COVID-19 Vaccine
Preparing the vials
- Mixing of the Medicago antigen with the adjuvant is required prior to administration.
- Check the expiry date on the antigen and adjuvant vials.
- Allow both the antigen and adjuvant vials to reach room temperature after removing from the refrigerator (no less than 20 minutes, no more than 60 minutes).
- Gently invert each vial 5 times or until homogeneity is obtained. Do not vortex, shake or mix vigorously.
- Inspect each vial for foreign matter, change in colour and / or leakage prior to mixing. If one of these conditions exists, the antigen or AS03 adjuvant vial must be discarded.
- The antigen content should be transparent to opalescent, colorless to yellowish liquid suspension. It may contain visible white particulates.
- The AS03 adjuvant content should be whitish to yellowish homogenous milky liquid emulsion.
Mixing
- Strict adherence to aseptic techniques must be followed.
- Hold and keep the adjuvant vial upside down. Use a 5 mL syringe (at least 21- gauge needle) to fully withdraw the entire content of the adjuvant vial and transfer it to the larger antigen vial.
- Do not mix with other products/vaccines in the same syringe.
- Gently invert the vial containing the mixed content a minimum of 5 times or until homogeneity is obtained. Do not shake.
- The concentration of the mixed vaccine, an emulsion for injection is 7.5 mcg / mL.
- Before use, inspect for foreign matter, change in colour and/or leakage. If one of these conditions exists, do not use the vaccine.
- The mixed vaccine should be a whitish to yellowish homogeneous milky liquid emulsion.
- Record the time that the components were mixed on the antigen vial label.
Administration
- Use the vaccine within 6 hours of mixing.
- Before each administration, gently invert the vial until homogeneity is obtained.
- Before administering, inspect for foreign matter, change in colour and/or leakage. If any of these conditions exists, do not administer.
- Cleanse the vial stopper with a single-use antiseptic swab, allow to dry.
- A 1 mL syringe with a 23-gauge needle for vaccine withdrawal and injection is recommended. Choose needle length based on the patient’s weight and make sure that the needle is tightly attached to the syringe.
- Withdraw a dose (0.5 mL) and administer into the deltoid muscle
- Store unopened vials in a refrigerator (2 °C to 8 °C). Do not freeze. If frozen, discard.
- Check the expiry date on the antigen and adjuvant vials. The shelf-life on outer cartons, containing both vials, is based on the component with the shorter expiry date.
- After mixing the antigen and adjuvant components, the vaccine must be used within 6 hours.
- Handle and store mixed vaccine at room temperature (20 °C to 30 °C). Protect from light. Do not refrigerate after mixing. If the vaccine is refrigerated, it must be discarded.
Disposal guidance for all vaccines
- Any unused vaccine or waste material should be disposed of in accordance with local requirements.
Specific populations: children, pregnant and breastfeeding individuals
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COVID-19 vaccines for children
NACI recommends that a complete series of pediatric mRNA vaccine be given to children ages 6 months -11 years who do not have contraindications to the vaccine. The pediatric Pfizer vaccine is the preferred vaccine in children ages 5-11, though the pediatric Moderna vaccine may be offered as an alternative in children ages 6-11.
Currently the Moderna vaccine is the only vaccine approved for children ages 6 months to 5 years.
Doses for children
Vaccines for children will be administered at a lower dose than for adults. The Pfizer vaccine will be administered at 10 mcg of mRNA in children ages 5-11, compared to the 30 mcg dose for ages 12 and over. The pediatric Moderna vaccine is also at a lower dose of 50 mcg for children ages 6-11 compared to 100 mcg for ages 12 and older. The Moderna vaccine for ages 6 months to 5 years will be administered at a dose of 25 mcg of mRNA which is 1/4 the dose for adults.
Schedules for children’s doses
The recommended interval between doses of the pediatric mRNA vaccine is 8 weeks (56 days). Children ages 5-11 years may receive other vaccines the same day as a COVID-19 vaccine.
It is recommended as a precaution that children ages 6 months to 5 years do not receive other vaccines on the same day as their COVID-19 vaccines, with a recommended 14 day window before or after other vaccines.
Children with a previous COVID-19 infection are recommended to wait 8 weeks after symptom onset or positive test result for vaccination (MOH, February 24, 2022, Health Canada, November 19, 2021, Health Canada, March 17, 2022, NACI, March 17, 2022; NACI, June 21, 2022; Health Canada July 14, 2022; NACI, July 14, 2022).
For moderately to severely immunocompromised children ages 5-11, NACI strongly recommends (NACI, June 21, 2022):
- A primary series of three doses of Pfizer pediatric vaccine with an interval of 4 to 8 weeks between doses
- A third dose of Pfizer pediatric vaccine 4 to 8 weeks after the second dose for children who have already received a two dose primary series
For moderately to severely immunocompromised children ages 6 months to 5 years, NACI recommends (NACI, July 14, 2022):
- A primary series of three doses of the Moderna vaccine (25 mcg) with an interval of 4 to 8 weeks between doses
For more information on the risks and benefits of the recommended interval for children’s vaccines, see CEP’s Recommended intervals between doses.
For tips on talking to parents about vaccination for their children, see CEP’s PrOTCT Plan for the COVID-19 Vaccine Discussion
COVID-19 vaccines and consent for children and youth under 18
Consent requirements differ between Public Health Units, with some requiring parental consent but not others. See Provincial vaccine rollout for links to all Public Health Unit websites.
In Ontario, there is no defined age of consent for vaccinations. Generally, children can consent to medical treatments as long as they are deemed capable of making an informed decision. This means that they must be able to understand information about the vaccine and what will happen if they accept or refuse vaccination. Children should talk about the benefits and risks of getting the vaccine with a trusted caregiver and their health provider. For a more detailed overview, see CMPA’s updated “How to address vaccine hesitancy and refusal by patients or their legal guardians” (Dec 2020).
Pregnant and breastfeeding individuals
During the initial development trials, some populations were not included in the clinical trials of the different COVID-19 vaccines.
NACI recommends that pregnant and breastfeeding individuals should be offered a complete vaccine series with an mRNA COVID-19 vaccine (NACI, January 14, 2022):
For patients planning a pregnancy:
- The COVID-19 vaccination series should ideally be completed ahead of pregnancy to help ensure maximal efficacy. It is not known whether an individual should delay pregnancy following receipt of the vaccine, and a risk-benefit discussion for those planning pregnancy should occur similar to the discussion for vaccination of pregnant and breastfeeding individuals (SOGC, November 4, 2021).
For patients planning the timing of vaccination during pregnancy:
- SOGC recommends that time-sensitive interventions such as administration of anti-D immunoglobulin and blood products should not be delayed on account of recent COVID-19 vaccination and could be given simultaneously (SOGC, November 4, 2021).
- NACI and SOGC recommend that a full series of vaccine should continue to be offered to individuals who become pregnant or detect pregnancy between doses (SOGC, November 4, 2021)
For patients who are breastfeeding:
- Breastfeeding can continue after getting vaccinated, it is not detected in breast milk and does not have an adverse impact on infants (MOH, September 29, 2021).
For patients impacted by limited vaccine supply:
- There are no physiologic reasons to anticipate that the effect of delaying the second dose of the COVID-19 vaccine would be different for a pregnant individual compared to a non-pregnant individual. Pregnant individuals may resume their vaccine series the same as the non-pregnant population in situations of supply chain interruptions (SOGC, November 4, 2021).
Emerging evidence: variants, specific populations, adverse events and vaccine dosage interval
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For patient-friendly answers to vaccine questions, see Ensuring patient confidence in vaccines.
For more detail on special populations and the COVID-19 vaccines, see OCFP’s COVID-19 Vaccination for Special Populations Information for family doctors.
Recommended intervals between doses
NACI and the Ontario Ministry of Health currently recommend an 8-week interval between mRNA vaccine doses. In light of the Omicron variant both NACI and the Ontario Immunization Advisory Committee continue to recommend this interval in order to optimize for a strong and robust immune response in children. Parents and guardians of children ages 5-11 may request an interval shorter than 8 weeks with informed consent (NACI, November 19, 2021; MOH, November 22, 2021; Public Health Ontario, December 23, 2021).
Risk
Optimal protection not achieved until after the vaccine series is completed.
Supporting evidence
- Although optimal protection is not achieved until after the full series is completed, the first vaccine dose does provide protection. For instance, data from Quebec indicated that one dose of mRNA vaccine provided substantial and lasting protection, extending at least four months post-vaccination (Clin Infect Dis, August 30, 2021).
Benefits
- Stronger immune response observed with an extended dose interval.
Supporting evidence
- One study in the United Kingdom found a 2- to 4-fold increase in neutralizing antibody levels 4 weeks after the second dose of the Pfizer-BioNTech Comirnaty vaccine when given at an extended dose interval of 6-11 weeks compared with the manufacturer’s recommended interval of 3-4 weeks. B cell response was also found to be 7-fold higher with the extended dose interval 4 weeks after vaccination (Cell, November 11, 2021).
- Another study in older adults aged 80 and older found that dual vaccination with the Pfizer-BioNTech Comirnaty mRNA vaccine with an extended interval induced antibody responses that were 2.9-times higher than with the AstraZeneca Vaxzevria vaccine (Immunity and Ageing, August 20, 2021).
- Greater vaccine effectiveness, which may last longer, seen with an extended interval.
- Data from British Columbia (BC) and Quebec found that mRNA vaccine effectiveness against SARS-CoV-2 infection was 91% in BC and 89% in Quebec with an extended 7-8 week interval compared to 85% in BC and 79% in Quebec with the manufacturer’s specified interval of 3-4 weeks (Preprint, medRxiv, October 26, 2021).
- The same study also showed higher vaccine effectiveness against hospitalizations with the extended interval at all time points, continuing more than 16 weeks after the completed vaccine series (Preprint, medRxiv, October 26, 2021).
- Other countries, such as the United Kingdom, have also found that extended intervals between doses has improved vaccine efficacy and has recommended that a longer interval schedule be implemented among the UK’s eligible population (UK Health Security Agency, November 30, 2021).
- Reduced risk of myocarditis/pericarditis, a rare adverse event, after the second dose.
- Emerging Canadian safety surveillance data suggest a lower risk of myocarditis/pericarditis with an extended vaccine interval (NACI, November 19, 2021).
- A study of all myocarditis/pericarditis cases reported following mRNA vaccination between December 14, 2020 to September 4, 2021 among individuals aged 12 and older in Ontario found that reported rates were higher with shorter dosing intervals (30 days or less) compared to longer intervals (56 days or more) (Preprint, medRxiv, December 5, 2021).
Mixing COVID-19 vaccines
Recent studies have demonstrated the safety and immune responses produced using mixed COVID-19 vaccine schedules, and therefore support vaccine interchangeability. Mixed dose schedules have also been used with similar vaccine products safely and effectively in other public health situations (flu, hepatitis A, etc.) (NACI, July 22, 2021). The Ontario government now recommends that individuals who have received AstraZeneca for their first dose receive AstraZeneca or an mRNA vaccine (Pfizer or Moderna) as their second dose, based on their preference. Second doses can be booked 28 days after a first dose of Pfizer/Moderna or 8 weeks after a first dose of AstraZeneca (MOH, June 2021; MOH, July 16, 2021; NACI, June 1, 2021). For patients who received an mRNA vaccine (Pfizer or Moderna) as their first dose, NACI and the Ontario government now recommend that if supply of the first dose vaccine is limited, a second dose can be provided using the alternative mRNA vaccine. It is still recommended to administer both doses with the same mRNA vaccine product, if supply permits (MOH, July 16, 2021; NACI, June 1, 2021).
Vaccine real-world effectiveness and impact on transmission
Efficacy is how well the vaccine works in clinical trials. An efficacy of 95% means that in clinical trials, the vaccine decreased the number of COVID-19 cases by 95% compared to the population that received the placebo injection.
Effectiveness is how well the vaccine protects in the real world. Because effectiveness includes less healthy people, it is usually lower than efficacy. An effectiveness of 95% means that in the real world, the vaccine decreased the number of COVID-19 cases by 95% compared to what we would expect in people who are not vaccinated.
How effective are the vaccines in the real world?
All of the COVID-19 vaccines approved for use in Canada are effective at preventing symptomatic SARS-CoV infection and COVID-19 related hospitalizations and death (PHO, August 25, 2021). Accurately determining the real-world effectiveness of vaccines in Ontario is challenging as it is dependent on a number of variables, including:
- The number of doses administered (e.g., three doses of mRNA vaccines are typically more effective than two)
- The timing of doses (e.g., effectiveness wanes over time)
- The COVID-19 variant that is most prevalent in Ontario (e.g., approved vaccines are less effective against Omicron than against previous variants)
- The completeness of the data with respect to the number of COVID-19 cases (e.g., during the Omicron surge, less available testing resulted in a less accurate estimate of the number of COVID-19 cases in the province at a given time)
Do the vaccines prevent transmission of COVID-19?
Early evidence suggests vaccination is associated with reduced spread in households, populations, regions, or facilities with higher rates of vaccination or those vaccinated earlier than others (PHO, March 19, 2021; PHO, June 2021). Furthermore, lower viral loads and reduced duration of infectiousness have been observed in vaccinated individuals infected with SARS-CoV-2 compared to those who are unvaccinated (PHO, June 2021).
Breakthrough infections
While vaccines provide effective protection against COVID-19, there have been some reported instances of breakthrough infections as no vaccine is 100% effective. Breakthrough infections are defined as cases that occur 14 days or more after the second dose of a 2-dose COVID-19 vaccine series (PHO, October 31, 2021; CDC, September 10, 2021).
In the period of December 14, 2020 – October 31, 2021, Public Health Ontario found that (PHO, October 31, 2021):
- 92.3% of COVID-19 cases were among unvaccinated individuals. 91.3% of hospitalizations and 90.6% of deaths occurred among unvaccinated individuals.
- 3.2% of cases were breakthrough cases among vaccinated individuals. Breakthrough cases accounted for 2.2% of hospitalizations and 2.8% of deaths.
COVID-19 Variants and vaccines
Variants of viruses are common and changes to the genetic material of the virus are expected over time. COVID-19 variants contain multiple mutations, including some in the receptor-binding domain (RBD) of the spike protein, which raises theoretical concerns over vaccine efficacy.
VOCs are being studied to understand their impact on the efficacy of COVID-19 vaccines. Early evidence is still emerging and being regarding vaccine efficacy against the Omicron variant. Currently, the understanding of vaccine efficacy against variants is as follows (COVID-END, May 21, 2021):
- Pfizer, Moderna, and AstraZeneca vaccines are thought to be effective against the Alpha variant (moderate certainty).
- Pfizer and AstraZeneca vaccines are thought to be effective against the Delta variant, with slightly lower effectiveness at preventing symptomatic disease caused by the Delta variant compared to the Alpha variant, but the same high effectiveness with respect to preventing hospitalizations from the two variants (Preprint, medRxiv, May 24, 2021).
Vaccine efficacy (including booster doses) and the Omicron variant
While preliminary data from Moderna and Pfizer show promising results of the efficacy of vaccine booster doses against the Omicron variant, the available evidence is not yet peer-reviewed. Research is ongoing to determine the efficacy of approved mRNA vaccines against the Omicron variant compared to other COVID-19 variants.
Current evidence:
- A study funded by Moderna notes that half-dose (50µg) boosters of Moderna increased immunity against Omicron approximately 37-fold compared to pre-booster levels. A full dose increased levels approximately 83-fold (Pre-Print, medRXiv, December 20, 2021).
- Preliminary data from Pfizer-BioNTech indicates that a third dose of their vaccine increases immunity to the Omicron variant 25-fold compared to two doses (Pfizer Inc., December 8, 2021).
- One case-controlled trial under review found that while two initial Pfizer-BioNTech or AstraZeneca doses provided no or limited protection against symptomatic disease from the Omicron variant, boosting with Pfizer-BioNTech significantly increased protection (Pre-Print, medRXiv, December 14, 2021).
- Data reported from the United Kingdom anticipates that, in conjunction with broader public health initiatives, booster doses will increase vaccine efficacy against the Omicron variant (Imperial College London, December 16, 2021).
Evidence limitations
Many studies on variants and vaccine efficacy test antibodies taken from vaccine recipients to determine their ability to neutralize synthetic spike proteins that are designed to resemble those of the variants. However, neutralization studies may not be an accurate proxy for vaccine efficacy; it is possible for a person with a reduced neutralizing antibody response to be fully immune (PHO, February 7, 2021).
A clinical trial evaluating the AstraZeneca vaccine suggested that it provides little protection against mild-moderate disease caused by the B.1.351 variant. However, the sample size in this trial was small, and it did not test the vaccine’s efficacy against severe disease or hospitalization (NEJM, March 16, 2021).
Omicron-targeted vaccines
Both Pfizer and Moderna have announced work on vaccines designed to protect against Omicron. These include both a monovalent and bivalent approach. Monovalent vaccines would target only the Omicron variant of COVID-19, while bivalent ones are designed to include mRNA that targets both the original strain of COVID-19 and variants of the virus. Though these vaccines are not yet approved and details are not finalized, Ontario plans to make Omicron-targeted vaccines available in the fall of 2022.
Pfizer
Pfizer has announced early results from studies on both a monovalent and bivalent vaccine. Their press release has indicated that the monovalent vaccine, given as a fourth booster dose, elicited a 13.5 and 19.6-fold increase in neutralizing geometric titers against Omicron BA.1 at 30 mcg and 60 mcg dose levels, respectively. The bivalent vaccine candidate exhibited a 9.1 and 10.9-fold increase against Omicron. These preliminary results suggest that both vaccines neutralize Omicron BA.4 and BA.5, though to a lesser extent than they do for BA.1 and both have a similar safety and tolerability profile to the original Pfizer COVID-19 vaccine. (Pfizer, June 25, 2022).
Moderna
A non peer-reviewed pre-print study details the results of Moderna’s bivalent vaccine, mRNA-1273.214. This vaccine targets both the original strain and the Omicron variant, containing 25 mcg of mRNA for each. This study examined the safety, reactogenicity, and immunogenicity of mRNA-1273.214 compared to the existing Moderna vaccine in patients who had previously received a two dose series and first booster of Moderna at least three months earlier. When compared to the original vaccine, the bivalent vaccine elicited an improved neutralizing antibody response against the omicron variant and a non-inferior neutralizing antibody response against the original strain. Safety and reactogenicity were found to be similar for both vaccines (Preprint, MedRxiv, June 25, 2022).
Rare vaccine adverse events
While many side effects of the COVID-19 vaccines are mild, some serious adverse events have been reported. Adverse events have been reported for both mRNA (Pfizer and Moderna) and viral vector (AstraZeneca and Janssen) vaccines, however these events are rare for all vaccine types.
Myocarditis/Pericarditis after mRNA vaccine
Since the spring of 2021, cases of myocarditis and/or pericarditis following immunization with a COVID-19 mRNA vaccine have been reported in a small number of people internationally and in Canada (Health Canada, June 30, 2021).
Most cases of myocarditis and/or pericarditis have been reported within 7 days of vaccination. While cases beyond this time range are rare, and other diagnoses should be considered, providers should report any events of myocarditis and/or pericarditis up to 42 days after vaccination (Hospital for Sick Children, August 6, 2021).
Patients should be advised to seek immediate medical attention if they develop any of these symptoms (PHAC, June 3, 2021):
- chest pain
- shortness of breath
- feeling of having a rapid or abnormal heart rhythm
Based on an analysis of the international cases, the individuals affected had predominantly mild cases of the condition and responded well to conservative treatment (e.g., NSAIDs) and rest (CDC, May 28, 2021; PHAC, June 3, 2021; Health Canada, June 30, 2021).
After an observed increase in Ontario of myocarditis/pericarditis (a very rare heart condition), the Government of Ontario is recommending that Pfizer be the preferred vaccine for Ontarians ages 18-24, out of an abundance of caution.
This decision is also influenced by the reliable availability of the Pfizer vaccines and the fact that individuals who received Moderna for their first dose can safely take the Pfizer-BioNTech vaccine for their second dose.
The risk of contracting myocarditis/pericarditis from the Moderna vaccine remains very low; while the risk of contracting the condition from COVID-19 is 18 times greater than from the vaccine. (Government of Ontario, September 29, 2021).
Despite this, the benefits of the mRNA vaccines continue to outweigh their risks in the authorized populations, as there are clear benefits of the vaccines reducing deaths and hospitalizations due to COVID-19 infections (PHAC, June 3, 2021).
For detailed primary care-specific guidance, algorithm, and frequently asked questions, see Myocarditis and Pericarditis After Covid-19 Vaccination: A Primer for Primary Care Professionals (U Waterloo/Focused Communication, August 2021).
Viral vector vaccines and adverse events
While viral vector vaccines (AstraZeneca and Janssen/Johnson & Johnson) are not currently being administered as first doses in Ontario, there are some rare adverse events providers should look for in patients who have received a dose of AstraZeneca.
These adverse events include:
- Guillain-Barré Syndrome (GBS)
- Capillary Leak Syndrome (CLS)
- Vaccine-induced Immune Thrombotic Thrombocytopenia (VITT)
The typical time frame of symptom onset for GBS and VITT ranges from 3-28 days after vaccination (Health Canada, August 6, 2021; Ontario COVID-19 Science Advisory Table, May 7, 2021). The time frame for CLS symptoms after vaccination is currently unknown. NACI recommends that patients with a history of CLS should not receive the AstraZeneca/COVISHEILD vaccine and should discuss options for COVID-19 vaccines with their healthcare provider (Health Canada, June 29, 2021).
Patients with the following symptoms after vaccination should seek immediate medical attention.
Guillain-Barré Syndrome (FDA, July 12, 2021):
- Weakness or tingling sensations, especially in the legs or arms, that’s worsening and spreading to other parts of the body
- Difficulty walking
- Difficulty with facial movements, including speaking, chewing, or swallowing
- Double vision or inability to move eyes
- Difficulty with bladder control or bowel function
Capillary Leak Syndrome (Health Canada, June 29, 2021):
- Rapid swelling of the arms and legs and/or sudden weight gain, in conjunction with feeling faint
Vaccine-induced Immune Thrombotic Thrombocytopenia (Ontario COVID-19 Science Advisory Table, May 7, 2021):
- Shortness of breath
- Difficulty speaking
- Severe chest, back or abdominal pain
- New severe swelling, pain or colour change in an arm or leg
- Sudden onset of severe or persistent worsening headaches or blurred or double vision
- Unusual bleeding or bruising (other than at the site of vaccination)
- New reddish or purplish spots or blood blisters
- Seizure
- Difficulty moving part of your body
Providers should report all cases of these adverse events following vaccination to their local health authority using the Ontario AEFI reporting form (MOH, April 29, 2021; PHO, May, 2021).
For more information on providing care for patients with these rare adverse events see:
Allergies and anaphylaxis
International safety monitoring of the Pfizer-BioNTech, Moderna, and AstraZeneca vaccines has identified a small number of cases of anaphylaxis after the vaccine. As millions of doses have been given worldwide, the Canadian Society of Allergy and Clinical Immunology (CSACI) identifies the risk for serious allergic reaction as low (CSACI, April 10, 2021).
With any vaccine, the potential for allergic reactions exists. Primary care providers can contact Ontario eConsult for allergy-related clinical questions. See Allergy advice for COVID-19 vaccine (eConsult, 2021).
Currently, Health Canada does not recommend receipt of any vaccine for the following populations:
- Persons with proven immediate or anaphylactic hypersensitivity to any component of the vaccine or its container, including polyethylene glycol.
- Individuals with a history of anaphylaxis after previous administration of the vaccine.
For individuals with allergies, CSACI recommends (CSACI, April 10, 2021):
- Assessment by an allergist is warranted in any individual with a suspected allergy to a COVID-19 vaccine or any of its components. Ontario has developed a sample allergy form to be used by allergist to document patient discussion (MOH, March 11, 2021).
- For ingredients lists (including in lay terms) see Pfizer ingredients, Moderna ingredients, AstraZeneca ingredients, and Janssen ingredients
- For information on Polyethylene glycol (PEG) allergies see Vaccine safety and adverse events > How do I know if I have a polyethylene glycol (PEG) allergy?
- Assessment by an allergist is NOT required for individuals with a history of unrelated allergies, including to allergies to foods, drugs, insect venom or environmental allergens. These individuals should be observed for a minimum of 15-30 minutes following vaccination.
- If there is a specific concern about a possible allergy to a component of the COVID-19 vaccine being administered, an extended period of observation post-vaccination of 30 minutes may be warranted; alternately, the vaccine can be administered in an emergency room setting, also with a prolonged observation period (BCCDC, June 2021).
People who experienced a severe immediate allergic reaction after a first dose of an mRNA COVID-19 vaccine can safely receive future doses of the same or another mRNA COVID-19 vaccine after consulting with an allergist or another appropriate physician. This group should also be observed for 30 minutes, instead of 15 minutes, after getting the vaccine.
Ensuring patient confidence in vaccines
Jump to concerns/questions related to:
For provider-focused information on current evidence, see Emerging evidence: specific populations, allergic reactions and extended vaccine dosage interval
PrOTCT PLAN for the COVID-19 vaccine discussion
As a primary care provider, you are the key to a successful COVID-19 vaccination campaign. These evidence-based responses to common questions will help you in your role as a community ambassador to promote widespread vaccination.
In all patient encounters, communicate that you and the members of your healthcare team have already gotten or are planning to get vaccinated.
“What do you think of the new vaccine(s)? Do you think I should get it? Is it safe?”
When patients ask these questions, it may be tempting to dive into answering. This framework will help approach these conversations thoughtfully to achieve a positive, effective interaction that builds trust while sharing important information.
Understanding vaccine hesitancy in Black communities
- The Black Scientists’ Task Force on Vaccine Equity is hosting a weekly series of town halls on a range of topics focused on Black community concerns and issues related to the COVID-19 pandemic, testing and vaccines. Videos of the town halls will be available for viewing on the group’s YouTube page after each town hall.
- Video: The Historical Issues of Trustworthiness & Medical Science that give Black People Cause for Concern
- Video: Misinformation & Conspiracy Theories (includes translation in American Sign Language)
- Resources and Video Series: Addressing COVID-19 Vaccine Distrust Among Black Patients (OMA)
Understanding vaccine hesitancy in Indigenous communities
- Indigenous Primary Health Care Council (IPHCC) resource: COVID-19 Vaccine – Common Beliefs Explored
- Webinar: Vaccine Hesitancy and First Nations, Inuit, and Métis Populations (NCCID, 2021)
- View the Wise Practices for COVID-19 Vaccinators webinar, March 23 1-2pm (will be recorded). Learn how to design and deliver high-quality, culturally safe vaccination services to First Nations, Inuit, and Métis people receiving their vaccinations through mainstream health services both on-reserve and in urban settings.
- Indigenous Primary Health Care Council (IPHCC) Course: Strategies to Support Indigenous Participation in Ontario’s COVID-19 Response
For Ontario providers
Use the following billing codes when counselling your patients about COVID-19 vaccine(s)/hesitancy:
- K080, 081, 082 (telephone/video)
- K013 (in person)
By-appointment phone service for Ontarians 12 years or older and their parents, caregivers or legal guardians to ask questions and discuss the vaccines with SickKids RNs.
Patients can book an appointment to speak live on the phone or chat with a physician about COVID-19 vaccines.
This Guide presents advice, scripts, and resources to help navigate conversations about COVID-19 vaccines with hesitant patients, including identifying, differentiating, and addressing common ‘types’ of vaccine hesitancy. Developed with clinicians from across Canada and with support from CEP.
The PrOTCT PLAN for the COVID-19 vaccine discussion
Addressing patient questions about…
Mix and match vaccine doses
For other public health concerns (flu, hepatitis A, etc.) people have safely been given a first dose of one vaccine and a second dose of a different vaccine. In order to be extremely cautious, the Canadian governments waited until information was available on doing this with COVID-19 vaccines. So far, this practice has been both safe and effective at preventing COVID-19.
The government of Ontario recommends that people who received a first dose of AstraZeneca receive AstraZeneca, Moderna, or Pfizer as a second dose, based on personal preference. People in other countries have done this, and what we know so far suggests that this has been both safe and effective at preventing COVID-19.
If you received a first dose of Moderna or Pfizer, it is recommended that you get the same vaccine for your second dose. However, the Ontario government recommends that these two vaccines may be ‘mixed and matched’ if supply is not available for the original vaccine you got.
COVID-19 vaccines for children
NACI and the Ontario Ministry of Health currently recommend an 8-week interval between mRNA vaccine doses. This applies to both the adult (ages 12+) and pediatric (ages 6 months to 11 years) vaccines available. While there is not yet direct data available from pediatric vaccines given at an 8-week interval, there is evidence from mRNA vaccines administered in adult populations. This evidence suggests that a longer dose interval of 8 weeks improves immune response and may provide longer lasting vaccine protection.
A longer interval between doses has also improved the duration of immunity in other types of vaccines, meaning this extended interval is consistent with general vaccine principles.
The recommended 8-week interval may also reduce the risk of the rare adverse event myocarditis/pericarditis following the second mRNA vaccine dose. NACI will continue to monitor and update this recommendation as further evidence becomes available (NACI, November 19, 2021; MOH, November 22, 2021; NACI, July 14, 2022).
For more information on supporting evidence on this question, see CEP’s Emerging Evidence section see Recommended intervals between doses
With the spread of new variants, children are at increased risk for severe disease, hospitalization and death from COVID-19. All eligible children should be vaccinated as soon as possible to protect them from this more contagious and more severe variant of COVID-19.
For more information on COVID-19 vaccinations in children and youth see COVID-19 vaccine for children and youth (Canadian Pediatric Society) or FAQs: Covid-19 mRNA Vaccines for Children (University of Waterloo)
Yes. The clinical trials for the Pfizer and Moderna vaccines showed that they are safe for children. Just like adults, many children had short-term, non-serious side effects like arm pain, fatigue, headaches, chills, muscle pain, fever, and joint pain.
Yes. Clinical trials showed 100% efficacy in children 12-15 (Pfizer) and 12-17 (Moderna) years of age. Clinical trials of the Pfizer vaccine in children ages 5-11 showed 90.7% efficacy. The Moderna vaccine showed the same efficacy in children ages 6-11 as it did in young adults (ages 18-25). Clinical trials of the Moderna vaccine in children ages 2-5 years and those 6-23 months showed 37% and 51% efficacy respectively.
This depends on which Public Health Unit you live in, as some units require parental consent and others do not. See Provincial vaccine rollout for links to all Public Health Unit websites.
In Ontario, there is no defined age of consent for vaccinations. Generally, children can consent to medical treatments as long as they are deemed capable of making an informed decision. This means that they must be able to understand information about the vaccine and what will happen if they accept or refuse vaccination.
The vaccine dose is determined by the age and maturity of the immune system, rather than the weight of the person receiving the vaccine. This is why the size of the child does not impact which version of the Pfizer vaccine they receive (child dose or adult dose for age 12+). The children’s version of the vaccine was shown to be effective in children aged 11 and to have fewer side effects with the smaller dose of mRNA. For this reason, children of this age will not benefit from receiving the adult (ages 12+) of the vaccine instead. The best option is to get your child protected through vaccination as soon as possible (Sickkids, November 19, 2021)
The AstraZeneca vaccine
A very small number of cases of Guillain-Barré Syndrome (GBS) have occurred in people who received the AstraZeneca COVID-19 vaccine. Fortunately, most people eventually recover from even the most severe cases of GBS. If you received your first dose of AZ over 25 days ago and have no symptoms, you are unlikely to be at risk for GBS as a result of receiving the vaccine.
A very small number of cases of capillary leak syndrome (CLS) have occurred in people who received the AstraZeneca COVID-19 vaccine. CLS is a very rare, serious condition that causes fluid leakage from small blood vessels.
The chance of CLS occurring is very low, but you should still be aware of the symptoms so that you can get fast medical treatment if it happens. Seek medical attention immediately if you have the following symptoms in the days after vaccination, in combination with feeling faint:
- rapid swelling of the arms and legs
- sudden weight gain
The AstraZeneca vaccine is associated with extremely rare cases of blood clots. These cases represent a small fraction of millions of doses delivered. While the cases are concerning enough to need investigation, it’s important to remember that the risk is very small, especially compared to the proven high risk of blood clots associated with COVID-19 infection.
If you received the AstraZeneca vaccine:
- More than 28 days ago: there is no cause for concern for blood clots.
- Less than 28 days ago: It is important to look for symptoms for 28 days, as it is easier to treat these rare clots if they’re found early. Seek immediate medical attention if you develop:
- shortness of breath
- difficulty speaking
- severe chest, back or abdominal pain
- new severe swelling, pain or colour change in an arm or leg
- sudden onset of severe or persistent worsening headaches or blurred or double vision
- unusual bleeding or bruising (other than at the site of vaccination)
- new reddish or purplish spots or blood blisters
- seizure
- difficulty moving part of your body
Adverse events are extremely rare following the AZ vaccine. For those who have already been vaccinated with AstraZeneca:
- More than 28 days ago: there is no cause for concern for blood clots or GBS.
- Less than 28 days ago: It is important to look for symptoms for 28 days. See the AstraZeneca/GBS and AztraZeneca/blood clots questions above for information on monitoring symptoms.
Focus on the benefits of the vaccine. During the 28 days after receiving the vaccine, your body is building up powerful immunity against COVID-19. There are also free online services for COVID-19 anxiety such as Wellness Together or MindBeacon that offer support groups, mindfulness, or therapy. You can also call 211 Ontario (2-1-1) to find local stress and mental health supports in your area.
The Moderna vaccine
No, you should not wait. The Pfizer and Moderna vaccines are very similar in how they work and how effective they are against COVID-19. Both are mRNA vaccines, and in clinical trials, they showed almost the exact same efficacy after one dose (92.6% for Pfizer and 92.1% for Moderna) and two doses (95.0% for Pfizer and 94.1% for Moderna).
The Pfizer and Moderna vaccines are indeed very similar. Hesitancy around the Moderna vaccine is likely due to people being more familiar with Pfizer as a company. It also may be because Canada has received many more Pfizer vaccines compared to Moderna. But the differences in quantities of vaccines are due to logistics, and have nothing to do with the effectiveness or safety of either vaccine.
mRNA vaccines
A very small number of cases of Guillain-Barré Syndrome (GBS) have occurred in people who received the Pfizer and Moderna COVID-19 vaccines. GBS is a very rare condition where your body’s immune system damages nerve cells. Fortunately, most people eventually recover from even the most severe cases of GBS.
At this time, the rate of GBS among people who received the Pfizer and Moderna vaccine is very low and is not higher than what is normally expected. However, you should still be aware of the symptoms so that you can get fast medical treatment if it happens. Seek medical attention immediately if you have the following symptoms in the days after vaccination:
- Weakness or tingling sensations, especially in the legs or arms, that’s worsening and spreading to other parts of the body
- Difficulty walking
- Difficulty with facial movements, including speaking, chewing, or swallowing
- Double vision or inability to move eyes
- Difficulty with bladder control or bowel function
The benefits of getting the Pfizer and Moderna vaccines continue to outweigh the harms. The important thing is protecting yourself from the very real risks of COVID-19 and all the vaccines approved in Canada will do that. Let’s talk about it and come to a decision together.
The purpose of all COVID-19 vaccines is to imitate the virus without making you sick. That way, your immune system can recognize the COVID-19 virus and stop future infections.
mRNA is something that your cells naturally use, every second of every day. mRNA is the recipe that tells your cells how to make proteins.
A COVID-19 mRNA vaccine has mRNA that tells your cells how to make the “spike protein” found on the outside of the COVID-19 virus. This spike protein cannot make you sick.
Your immune system “reads” the spike protein that our cells made, and builds antibodies and white blood cells to fight it. Then if you are infected with COVID-19, your immune system will recognize the spike protein that covers each virus, and can fight off the infection.
Your body quickly destroys the vaccine after making spike proteins. It does not stay in your body for long and does not make any long-term changes, other than helping you build your antibodies and white blood cells.
No. mRNA vaccines cannot change your DNA. Human beings do not have the enzymes to convert RNA into DNA. The vaccine doesn’t contain those enzymes either. In fact, our cells have enzymes that destroy the mRNA after the protein is made – which is why the vaccine doesn’t stay in your body for long.
Reports show that a small number of people experienced mild heart inflammation after receiving an mRNA vaccine in Canada and around the world. So far, the cases are more common in teenagers and young adults, males than females, occur after the second dose of the vaccine and typically happen within seven days after vaccination.
Viruses, and the body’s immune response to infection, typically cause this type of heart inflammation. It is important to know that this condition is rare, often has no symptoms, heals on its own, and is easily treated.
If you or someone you know experience the following symptoms after receiving an mRNA vaccine, seek medical attention: chest pain, shortness of breath, or feelings of having a fast-beating, fluttering, or pounding heart.
Viral vector vaccines
The purpose of all COVID-19 vaccines is to imitate the virus without making you sick. That way, your immune system can recognize the COVID-19 virus and stop future infections.
A COVID-19 viral vector vaccine has a piece of DNA (a gene) that tells your cells how to make the “spike protein” found on the outside of the COVID-19 virus.
In order to get the spike protein DNA into your cells, the DNA is placed in a hollow, harmless virus that is not COVID-19. This virus is called a viral vector, and it cannot make you sick.
Once in your cells, the DNA tells your cells how to make the spike protein. The spike protein cannot make you sick.
Your immune system “reads” the spike protein that your cells made, and builds antibodies and white blood cells to fight it. Then if you are infected with COVID-19, your immune system will recognize the spike protein that covers each virus, and can fight off the infection.
Your body quickly destroys the vaccine after making spike proteins. It does not stay in your body for long and does not make any long-term changes, other than helping you build your antibodies and white blood cells.
No. Viral vector vaccines cannot change your DNA. Human beings do not have the enzymes to insert the vaccine DNA into our DNA. The vaccine doesn’t contain those enzymes either.
COVID-19 risk and transmission
COVID-19 is much more serious than the flu. The risk of death is 3.5 times higher for COVID-19 than influenza (CMAJ, 2021).
COVID-19 is very contagious and can cause serious illness. More than 28,000 Canadians and over 728,000 Americans have died of COVID-19.
Even if a young and healthy person does not die of COVID-19 infection, they may have long term complications from COVID-19, affecting multiple organ systems. Long-term effects include memory loss, fatigue, body aches, unexplained breathing difficulties, and damage to the lungs and heart. Clinics have already been set up to support the many COVID-19 patients who, although they are no longer infected, cannot go back to work or live a normal life.
Even if a young and healthy person does not develop severe COVID-19 infection, you may still pass on the virus to someone who will. If you are vaccinated, you’re helping protect the people around you. Vaccination is the only way to end this pandemic. Vaccination helps protect against serious disease. I and all the members of the healthcare team around you have been immunized. You can protect yourself, your loved ones, and your community by getting vaccinated.
Even if you had COVID-19 in the past, it is uncertain how long the antibodies will last. You should still get the vaccine to protect yourself and others.
At this time, we know that it typically takes a few weeks for the body to develop immunity after vaccination. Therefore, it is possible that a person could be infected with the virus that causes COVID-19 just before or just after vaccination and then get sick because the vaccine did not have enough time to provide protection.
That being said, we also know that the vaccines protect most vaccinated people from getting sick with COVID-19. For those who still get sick, they appear to get a milder case. However, studies are ongoing as to how the vaccine affects how contagious infected people are.
It is important to continue public health measures of distancing and masking even after vaccination, until scientific experts say it is safe to stop.
Regular exercise and healthy eating can improve your immune system and overall health. But neither can cause your body to produce the antibodies and white blood cells that specifically protect you from COVID-19. Your immune system needs to be trained to produce these, and all approved COVID-19 vaccines help your immune system do this, regardless of the type of vaccine (e.g., mRNA, viral vector, etc.).
There is no evidence that homeopathic treatments can prevent COVID-19 or any other infections (Health Canada, 2019).
Specific populations and contraindications
All of the COVID-19 vaccines approved in Canada are safe and highly effective for use in pregnant and breastfeeding people. The social media rumours about the vaccines affecting fertility or the vaccines putting pregnant people at an increased risk of an extremely rare blood clot are untrue. There is no scientific evidence to support either of these rumours.
People who are pregnant are at higher risk of serious adverse events from COVID-19. It is strongly recommended that all pregnant individuals get vaccinated against COVID-19. Let’s discuss the benefits and risks and come to a decision together.
All COVID-19 vaccines are safe and effective for older people. Getting the vaccine is an important step to help prevent becoming sick with the virus.
Serious adverse events and anaphylaxis are very rare with the COVID-19 vaccines, occurring in only 0.006% of doses given. Unless you have a history of allergic reaction to components of the vaccine, or to the first dose of the vaccine, Health Canada recommends vaccination.
It is always advised to wait at least 15 minutes after receiving a vaccine, since an allergic reaction or anaphylaxis is always a possible reaction to any medication or vaccination. For those with a history of allergies, even to food, pets or other non-medical causes, waiting 30 minutes after receiving a vaccine is recommended.
Some patients may be allergic to an ingredient in one, but not another. On this site you can also review the vaccine ingredients in non-medical terms for the Pfizer-BioNTech, Moderna.
For references and further information, see our Top Resources.
It is important that new vaccines be tested in diverse populations to ensure that they are safe and effective for everyone. All COVID-19 vaccine trials included people of colour who were both racially and ethnically diverse. Collectively, the trial participants included those identifying as Black, American Indian/Alaska Native, Asian, Native Hawaiian/other Pacific Islander, Hispanic/Latino and multiracial.
Yes, you can take all of the approved vaccines. None of the approved vaccines in Canada contain live viruses, and neither do any of the vaccines that Canada has purchased but not yet approved.
For more information on the different types of COVID-19 vaccines, see Types of COVID-19 vaccines.
Religious beliefs
The Canadian Council of Imams and other Muslim bodies in Canada have stated that they consider the Pfizer-BioNTech, Moderna, and AstraZeneca vaccines to be permissible and will continue to evaluate other approved vaccines (Canadian Muslim COVID-19 Taskforce, 2021).
The Canadian Conference of Catholic Bishops have stated that all approved COVID-19 vaccines are permissible for Catholics. They indicate that Catholics are invited to be vaccinated to contribute to the safety of others (Canadian Conference of Catholic Bishops, March 11, 2021).
Some patients may have questions regarding their religion and receiving COVID-19 vaccines.
Many religious organizations have issued statements that encourage COVID-19 vaccination for the health and safety of individuals and their communities, following the advice of patients’ healthcare providers.
These organizations include:
Preparing for vaccination
While no research has been done to look specifically at whether COVID-19 vaccines are affected by Tylenol or Advil, earlier research has suggested that some drugs may affect immune response to other vaccines. To ensure the vaccine works properly, don’t take Tylenol or Advil immediately before your vaccination appointment. It’s ok to take either of these medications to reduce discomfort in the days after your vaccination.
No. As the vaccines target the immune system, they will not interact with medications such as statins. While certain immunosuppressants may slightly reduce the efficacy of the vaccine, there are no known drug interactions that will cause harm, prevent medications from working, or prevent the vaccine from working. There are some drugs not recommended to be taken with “live” vaccines, however no live vaccines are being considered for approval in Canada.
Vaccine availability and rollout
Your appointment for your second dose must be at least:
- 8 weeks after your first dose of AstraZeneca
- 28 days after your first dose of Moderna or Pfizer
The timing of your second dose appointment will depend on local considerations, vaccine supply, and the date of your first dose appointment. To book your second dose appointment, visit the provincial booking system.
- The pandemic – and the lockdowns and public health measures – will not end until the majority of Canadians are vaccinated. To ensure we can vaccinate everyone as quickly as possible, it is important that people access the vaccine the first time it is offered to them.
- Canada has ordered more than enough vaccines – we have purchased more shots per person than any other country in the world! We will be getting those vaccines delivered over time. The implementation plan of those vaccines is designed to most efficiently end this pandemic. You can feel confident that when you are offered one, it is because it is the right time for you to get it. This is your chance to do your part to end the pandemic and get back to normalcy quickly.
- If you wait to get vaccinated and get infected in the meantime, you may end up in hospital – which would put more strain on the system than getting the vaccine.
- If Canadians wait to get the vaccine, the pandemic will keep going – and that includes the restrictions, inability to see family and friends, send your kids to school, travel.
- If Canadians wait to get the vaccine, more people will die.
For references and further information, see our Top Resources.
Details about Ontario’s rollout of a possible bivalent vaccine for the fall are not yet finalized. However, a press conference featuring Ontario’s Chief Medical Officer indicated that receiving a second booster will not interfere with eligibility for a bivalent vaccine in the fall. Receiving a second booster dose now may impact the timing of eligibility to receive a bivalent vaccine in the fall but will not impact eligibility (Chief Medical Officer of Health of Ontario, Press Conference, July 13, 2022; MOH, July 14, 2022).
Ontarians in certain demographics are encouraged to get a second booster as soon as possible with the knowledge that it will not make them ineligible for a bivalent dose in the fall. These include (Chief Medical Officer of Health of Ontario, Press Conference, July 13, 2022; Toronto Public Health, July 13, 2022):
- Individuals aged 60+
- First Nation, Inuit and Métis individuals aged 18+ and their non-Indigenous household members
- Residents of a long-term care home, retirement home, or Elder Care Lodge and older adults living in other congregate settings that provide assisted-living and health services
- Individuals aged 18+ who are moderately to severely immunocompromised
- Individuals aged 18+ who have underlying health conditions
- Individuals aged 18+ for which it would be beneficial based on personal factors like exposure at work or home
- Individuals aged 18+ who would come into close contact e.g., healthcare workers and other support staff, family, friends, caregivers) with those who are immunocompromised
Details about Ontario’s rollout of a possible bivalent vaccine for the fall are not yet finalized. However, a press conference featuring Ontario’s Chief Medical Officer indicated that the expected wait time between a second booster and a bivalent vaccine dose would be between 3-5 months. Three months would be a typical interval for those who are immunocompromised and five months would be typical for those who are lower risk. Receiving a second booster dose now may impact the timing of eligibility to receive a bivalent vaccine in the fall due to the typical intervals between doses but will not impact eligibility for the vaccine (Chief Medical Officer of Health of Ontario, Press Conference, July 13, 2022; MOH, July 14, 2022).
Vaccine development and approval process
- No steps were skipped in the process of developing, testing, approving, and producing the vaccines.
- Canada’s best independent scientists have thoroughly reviewed all the data before approving the vaccines as safe and effective for Canadians.
- The vaccines were produced faster than before not because of skipped steps but because of never-before-seen levels of collaboration and funding around the world invested in this effort. Normally, vaccine clinical trials need 6000-8000 people for the approval process.
- The Pfizer-BioNTech trial had over 43,000 people.
- The Moderna trial had over 30,000 people.
- The AstraZeneca trial had over 11,000 people.
- The Johnson & Johnson trial had over 44,000 people.
- Unlike with other vaccines that go one step at a time and then plan the next step, for the COVID-19 vaccines, governments invested in having companies plan all the steps at the beginning and build up their manufacturing capacity right away.
For references and further information, see our Top Resources.
The use of mRNA and viral vectors for vaccines and treatment of disease has been around for a while – that’s one of the reasons why these vaccines could be developed so quickly. mRNA vaccines have been used in animal models for influenza, Zika, Rabies, CMV and others, and in humans for cancer treatment and cancer vaccine clinical trials. Viral vector vaccine technology has been used for Ebola outbreaks, and a number of studies have focused on viral vector vaccines against other infectious diseases such as Zika, flu, and HIV.
For references and further information, see our Top Resources.
- The pharmaceutical companies manufacture the vaccine and sponsor and conduct the clinical trials, but all vaccine clinical trials must have an independent data and safety monitoring board review the vaccine efficacy and unblind the data.
- As the trial is completed, Health Canada reviews all safety and efficacy data before allowing the vaccine to be used in the Canadian population.
- After a vaccine has been approved for use and made available, its safety is continuously monitored by healthcare providers and Canada-wide networks specifically designed for safety. Health Canada monitors national and international vaccine safety reports and will update information about the vaccine as it becomes available.
Health Canada provides ongoing safety monitoring for the vaccines. You can see the most recent data at reported side effects following COVID-19 vaccinations in Canada (Health Canada)
For references and further information, see our Top Resources.
Side effects
- The vaccines cannot give you COVID-19 or any other infectious disease. None of the licensed vaccines so far use the live virus that causes COVID-19.
- It is still possible to contract COVID-19 after you have been vaccinated. Like with other vaccinations, it takes a few weeks for the body to build immunity after vaccination. Someone could be infected with the virus just before or just after vaccination and get sick, because the vaccine didn’t have enough time to provide protection.
References
- Pfizer-BioNTech COVID-19 Vaccine Info Sheet (MOH, December 13, 2020)
- Details for: Pfizer-BioNTech COVID-19 vaccine (Health Canada, Nov 13, 2020)
- Consumer information: Details for Moderna COVID-19 vaccine / vaccin de Moderna contre la COVID-19 (Health Canada, Dec 23, 2020)
- Viral Vector-based Vaccines for COVID-19.
- With any of the approved vaccines people can expect to feel a sore arm, a bit of tiredness and a mild headache as the vaccine starts to work. Some people will feel muscle aches, chills, or a mild fever.
- For more information on how common side effects were in the Pfizer-BioNTech clinical trial, see its Clinical trial details.
- For more information on how common side effects were in the Moderna clinical trial, see its Clinical trial details.
- For more information on how common side effects were in the AstraZeneca clinical trial, see its Clinical trial details.
- For information about AstraZeneca and rare blood clots see questions about the AstraZeneca Vaccine
- For more information on how common side effects were in the Janssen clinical trial, see its Clinical trial details.
References
- Among the almost 22,000 vaccinated with the Pfizer-BioNTech COVID-19 vaccine, there were 4 cases of Bell’s palsy. This number of Bell’s palsy cases is consistent with the expected rate in the general population and did not suggest it was caused by the vaccine. Three cases occurred within one month after both doses were completed, and one case occurred later than one month after both doses were completed, and all four patients recovered.
- More research will be conducted as this was the only “imbalanced” occurrence that happened more in the vaccine arm of the study than the placebo arm.
- Those with previous history of Bell’s palsy may still take this vaccine.
References
- Vaccines and Related Biological Products Advisory Committee Meeting December 10, 2020 FDA Briefing Document Pfizer-BioNTech COVID-19 vaccine
- Product monograph, including patient medication information: Pfizer-BioNTech COVID-19 vaccine (February 8, 2021)
- Fact check: Clarifying claims around Pfizer vaccine deaths and side effects (Reuters, December 10, 2020)
- Yes. Mild side effects are common for all vaccines.
- There could be soreness and swelling which for some might be significant (sometimes from shoulder to elbow). In these cases:
- Use cold compresses over the site.
- Know that local reactions, even big ones, improve by 48-72 hours. If the reaction worsens at 72 hours or has not disappeared in 5 days, seek medical attention.
- Even though sometimes this reaction can look like an infection, the risk of skin/local infection from a vaccine needle is very small. These reactions do not need any antibiotics in the first 72 hours.
- If the swelling progresses rapidly, is associated with breathing problems, or makes you very concerned about an allergic reaction, seek urgent medical attention and/or call 9-1-1.
Vaccine safety and adverse events
No. “Long COVID” symptoms are caused by the virus, and the vaccines do not contain any virus. Side effects from the vaccine are common and should resolve within a few days.
- Since the vaccines are new, studies are ongoing to determine how long the immunity lasts or if there are long-term side effects. The long-term data we’re still waiting for is more about long-term efficacy (how long immunity lasts) than long-term safety.
- It is very unlikely for long-term effects to develop, as these initial vaccines are not live vaccines and side effects most often present in the first few days after vaccination.
Polyethylene glycol (PEG) allergies are rare. PEG is a common ingredient found in many products, and most people use these products without having any allergic reactions.
If you have used any of the following medications without allergies, you are not allergic to PEG:
- Extra Strength Tylenol, Tylenol EZ tabs, Tylenol Gel Caps
- Advil Liqui-Gels
- Benadryl 25 or 50mg pink caplets
- Laxaday
- Go-Lytely
- Reactine 5 or 10mg tablets
- Enteric coated daily low dose aspirin (81 mg)
To identify PEG on a label, look for:
- “Polyethylene glycol”
- PEG followed by a number (PEG-40).
- PEG followed by a number and then another ingredient name (PEG-20 cocamine)
- Complex PEG compounds with many slashes, but will always contain “PEG” (BIS-PEG/PPG-16/16 PEG/PPG-16/16 Dimethicone)
Vaccine ingredients
- No. They do not contain mercury, formaldehyde, aluminum, or fetal cells.
- On this site you can review a list and explanation of:
Questions specific to Indigenous communities
It’s natural to question the motive as to reasons why Indigenous Peoples are identified as a priority.
Along with healthcare workers and residents of long-term care/retirement homes, Indigenous Peoples have been identified as a priority population because evidence shows they are among those at greatest risk of serious, life-threatening implications if they contract COVID-19.
Moreover, chronic medical conditions with a greater prevalence among Indigenous Peoples such as respiratory disease, heart disease, diabetes, kidney and liver disease, have been found to be at greater risk of more severe outcomes from COVID-19 (IPHCC, 2021).
Update Vaccines and COVID-19 variants
The Canadian and provincial governments are monitoring cases of new COVID-19 variants in Canada.
Early data suggests that these variants may be more easily transmitted and may impact the severity of disease. There is some evidence to suggest that some variants of COVID-19 may have an impact on the efficacy of approved COVID-19 vaccines. However, real world studies so far have shown that the approved vaccines are effective against the variants present in Canada.
Additional research is ongoing to learn more about these variants.
It is normal for viruses to change and develop different versions (variants), and there is a risk that certain changes may make COVID-19 more resistant to vaccines. For example, early evidence suggests that vaccines may not be as good at protecting people from the variant originating in South Africa.
Luckily, vaccine companies are doing research to update their vaccines to better protect against variants of concern. The best way you can help reduce the spread of COVID-19 variants is to continue to follow public health guidelines.
More research is being done to understand COVID-19 vaccines and immunity. However, data collected from vaccines administered at an extended interval indicate that this approach provides stronger immunity and is better for optimal immune response. For this reason, Ontarians that choose to receive a second booster dose in the summer may have to wait longer to access an Omicron targeted dose in the fall in order to achieve the most effective interval between doses and provide optimal protection overall (Clin Infect Dis. April 19, 2022; Alberta Health Services, July 20, 2022). Data from Israel, where second boosters were administered earlier than in Canada, indicate that rates of COVID-19 infection and severity of illness were lower after a fourth dose of mRNA vaccine. While immunity against confirmed infection waned, protection against severe disease did not (NEJM, May 5, 2022).
Vaccine efficacy
Efficacy means how well the vaccine works in clinical trials. An efficacy of 95% means that in clinical trials, the vaccine decreased the number of COVID-19 cases by 95% compared to the population that received the placebo injection.
But clinical trials are not real-world conditions. For example, people in clinical trials are generally healthy, because researchers do not want to include people who are sick or are taking certain medications.
Effectiveness means how well the vaccine protects in the real world. Because effectiveness includes less healthy people, it is usually lower than efficacy. An effectiveness of 95% means that in the real world, the vaccine decreased the number of COVID-19 cases by 95% compared to what we would expect in people who are not vaccinated.
Information so far suggests that the approved vaccines are very effective in the real world. Clinical trials already showed that all 4 approved vaccines have high efficacy.
No. Vaccinated individuals can still be infected, but vaccination greatly reduces the risk of infection, and reduces the risk of an infection progressing to the more severe form of the disease.
When an individual tests positive for COVID-19 14 days or more after the second dose of a 2-dose COVID-19 vaccine series, this is known as a breakthrough infection. In Ontario, the rate of breakthrough infections among fully vaccinated individuals has been very low.
In the period of December 14, 2020 – August 21, 2021, Public Health Ontario found that (PHO, August 31, 2021):
- 94.8% of COVID-19 cases were among unvaccinated individuals. 92.4% of hospitalizations and 92.1% of deaths occurred among unvaccinated individuals.
- 0.9% of cases were breakthrough cases among vaccinated individuals. Breakthrough cases accounted for 0.9% of hospitalizations and 1.3% of deaths.
No. An effectiveness of 95% means that the vaccine decreased the number of COVID-19 cases by 95% compared to the population that received the placebo injection. While it is still possible for vaccinated people to get COVID-19, an effectivess of 95% does not mean that 5% of vaccinated people will still get the virus
- The AstraZeneca clinical trials show protection starts from approximately 3 weeks after receiving the first dose and persists up to 12 weeks. A second dose should be given at a 4-to-12-week interval after the first dose, with evidence that suggests the vaccine increases effectiveness with longer intervals between doses.
- Pfizer-BioNTech’s clinical trials show that individuals may not be optimally protected until at least 7 days after their second dose of vaccine, given 21 days after the first dose.
- Moderna’s clinical trials show that individuals may not be optimally protected until after receiving the second dose of the vaccine, given 28 days after the first dose.
References
When scientists measure efficacy and effectiveness, they focus on symptomatic COVID-19 cases. So even with a highly effective vaccine, it is possible for people to develop infections without symptoms. These asymptomatic people can spread COVID-19 to others close to them. Preventing symptomatic cases helps, but in order to better protect against transmission, vaccines must also be able to prevent asymptomatic COVID-19 infections.
Scientists are researching how well the COVID-19 vaccines prevent these asymptomatic cases and how well they prevent transmission. The information we have so far suggests that the Pfizer-BioNTech and Oxford-AstraZeneca vaccines do this well (Preprints with The Lancet, February 1, 2021; Authorea Preprint, February 24, 2021).
The information we have so far suggests that the approved vaccines do this well.
Though we are still learning how many people have to be vaccinated against COVID-19 before most people can be considered protected, it’s currently estimated that 40% – 90% vaccination coverage is required to achieve herd immunity for COVID-19.
References
- Key Things to Know About COVID-19 Vaccines (CDC, March 8, 2021)
- COVID-19 – What We Know So Far About… Herd Immunity (Public Health Ontario, January 15, 2021)
Types of COVID-19 vaccines
There are four main categories of COVID-19 vaccines that are under development (GAVI, 2021):
- Nucleic acid vaccines, which include mRNA vaccines and DNA vaccines
- Subunit vaccines, which include protein subunit vaccines and virus-like particle (VLP) vaccines
- Viral vector vaccines
- Whole virus vaccines, which include inactivated vaccines and live-attenuated vaccines
Different types of vaccines offer different advantages and disadvantages, in terms of how easy they are to manufacture and store, as well as the level of immunity they invoke (GAVI, 2021).
Click for details:
Are there other vaccines of this type available in Canada?
- No. These are the first mRNA vaccines available in Canada.
Are there COVID-19 vaccines of this type approved by Health Canada?
- Pfizer-BioNTech and Moderna are currently the only approved mRNA vaccines.
How do these vaccines work?
- mRNA vaccines contain genetic material from the COVID-19 virus (called mRNA) that gives human cells instructions to make specific COVID-19 proteins.
- After our cells make copies of the protein, our cells destroy the mRNA.
- The human immune system learns to recognize these COVID-19 proteins and develops antibodies and white blood cells against them, which provides immunity against COVID-19 in the future.
Are these “whole virus” vaccines?
- No. mRNA vaccines only contain part of COVID-19’s genetic material (mRNA), and do not contain any of its proteins.
Can these vaccines cause COVID-19 disease?
- No. mRNA vaccines don’t contain the entire COVID-19 genome or any of its proteins, all of which are necessary for COVID-19 to cause disease.
What are some of the advantages and disadvantages of this type of vaccine?
- Advantages:
- Immune response is strong as it involves B cells and T cells
- No live components, so no risk of the vaccine triggering disease
- Relatively easy to manufacture
- Disadvantages:
- Some RNA vaccines require ultra-cold storage
- Never been licensed in humans
- Booster shots may be required
Are there other vaccines of this type available in Canada?
- No. There are no DNA vaccines approved in Canada for diseases other than COVID-19.
Are there COVID-19 vaccines of this type approved by Health Canada?
- No. There are no COVID-19 vaccines of this type approved by Health Canada at this time.
How do these vaccines work?
- DNA vaccines contain genetic material (DNA) that gives human cells instructions to make specific COVID-19 proteins.
- The DNA is first inserted into a circular piece of bacterial DNA, which is called a plasmid (these are widely used in genetic engineering).
- Plasmids are then injected into a person’s muscle. Different vaccines use different approaches to make sure that the plasmid can enter human cells once inside the muscle.
- Once the plasmid is inside our cells, our cells make copies of the COVID-19 protein.
- The human immune system learns to recognize these COVID-19 proteins and develops antibodies and white blood cells against them, which provides immunity against COVID-19 in the future.
Are these “whole virus” vaccines?
- No. DNA vaccines only contain genetic material (DNA) with some of COVID-19’s genes, and do not contain any of its proteins.
Can these vaccines cause COVID-19 disease?
- No. DNA vaccines don’t contain the entire COVID-19 genome, or any of its proteins, all of which are necessary for COVID-19 to cause disease.
What are some of the advantages and disadvantages of this type of vaccine?
- Advantages:
- Immune response is strong as it involves B cells and T cells
- No live components, so no risk of the vaccine triggering disease
- Relatively easy to manufacture
- Disadvantages
- Never been licensed in humans
- Booster shots may be required
Are there other vaccines of this type available in Canada?
- Yes, including the SHINGRIX shingles vaccine.
Are there COVID-19 vaccines of this type approved by Health Canada?
- Novavax Nuvaxovid is the only vaccine of this type approved by Health Canada at this time.
How do these vaccines work?
- Subunit vaccines contain pieces of the COVID-19 virus (in this case, pieces of COVID-19 proteins).
- The human immune system learns to recognize these proteins and creates antibodies, which provides immunity against COVID-19 in the future.
- Because the COVID-19 proteins cannot infect cells, only part of the immune system (i.e. antibodies) can react to them. Adjuvant medications and/or booster doses may be required.
Are these “whole virus” vaccines?
- No. Protein subunit vaccines only contain pieces of specific COVID-19 proteins, and do not contain all of its proteins, or any genetic material.
Can these vaccines cause COVID-19 disease?
- No. Protein subunit vaccines don’t contain all of COVID-19’s proteins, or any of its genes, all of which are necessary for COVID-19 to cause disease.
What are some of the advantages and disadvantages of this type of vaccine?
- Advantages:
- Well-established technology
- Suitable for people with compromised immune systems
- No live components, so no risk of the vaccine triggering disease
- Relatively stable
- Disadvantages
- Relatively complex to manufacture
- Adjuvants and booster shots may be required
- Determining the best antigen combination (i.e., mix of protein pieces) takes time
Are there other vaccines of this type available in Canada?
- Yes, including all HPV vaccines.
Are there COVID-19 vaccines of this type approved by Health Canada?
- The Medicago vaccine is the only vaccine of this type approved by Health Canada at this time.
How do these vaccines work?
- Virus-like particle vaccines contain COVID-19 proteins that are assembled into something resembling a COVID-19 virus, but without COVID-19’s genetic material.
- The human immune system learns to recognize these COVID-19 proteins and develops antibodies and white blood cells against them, which provides immunity against COVID-19 in the future.
Are these “whole virus” vaccines?
- No. Although virus-like particle vaccines physically resemble the virus to a degree, they do not contain any of COVID-19’s genetic material, and do not contain all of its proteins.
Can these vaccines cause COVID-19 disease?
- No. Virus-like particle vaccines don’t contain all of COVID-19’s proteins, or any of its genes, all of which are necessary for COVID-19 to cause disease.
What are some of the advantages and disadvantages of this type of vaccine?
- Advantages:
- Immune response is strong as it involves B cells and T cells
- Suitable for people with compromised immune systems
- No live components, so no risk of the vaccine triggering disease
- Disadvantages:
- Relatively complex to manufacture
- Relatively temperature sensitive, so careful storage necessary
Are there other vaccines of this type available in Canada?
- No. There are no viral vector vaccines approved for other human diseases in Canada, there are viral vector vaccines available in other countries, such as the Merck Ebola vaccine.
Are there COVID-19 vaccines of this type approved by Health Canada?
- Yes. Oxford-AstraZeneca and the Janssen (Johnson & Johnson) vaccine are both approved by Health Canada.
How do these vaccines work?
- Viral vector vaccines contain a weakened version of a live virus that is not the COVID-19 virus. This weakened virus (which is often an adenovirus), is called a “viral vector”, and has genetic material from the COVID-19 virus inserted inside it.
- Once the viral vector is inside human cells, the COVID-19 genetic material gives cells instructions so that they can make specific COVID-19 proteins.
- The immune system learns to recognize these proteins and develops antibodies and white blood cells against them, which provides immunity against COVID-19 in the future.
Are these “whole virus” vaccines?
- No. Viral vector vaccines only contain certain genetic material from COVID-19, not the entire genome, and the protein “shell” containing these pieces of genetic material belongs to a different type of virus (e.g., a harmless adenovirus).
Can these vaccines cause COVID-19 disease?
- No. Viral vector vaccines don’t contain the entire COVID-19 genome or any of its proteins, all of which are necessary for COVID-19 to cause disease.
What are some of the advantages and disadvantages of this type of vaccine?
- Advantages:
- Immune response is strong as it involves B cells and T cells
- Well-established technology
- Disadvantages:
- Previous exposure to the vector (e.g., adenovirus) could reduce effectiveness
- Relatively complex to manufacture
Are there other vaccines of this type available in Canada?
- Yes, including all flu shots (nasal spray is live-attenuated).
Are there COVID-19 vaccines of this type approved by Health Canada?
- No. There are no COVID-19 vaccines of this type approved by Health Canada at this time.
How do these vaccines work?
- Inactivated vaccines contain whole COVID-19 viruses whose genetic material has been destroyed by heat, chemicals or radiation.
- These viruses cannot infect cells and replicate, and therefore may be safer than live-attenuated vaccines for those who are immunocompromised.
- Because the inactivated viruses cannot infect cells, only part of the immune system (i.e. antibodies) can react to them. Adjuvant medications and/or booster doses may be required.
Are these “whole virus” vaccines?
- Yes, but the virus is not live as its genetic material has been destroyed.
Can these vaccines cause COVID-19 disease?
- No. Inactivated vaccines cannot cause COVID-19 disease because the COVID-19 genetic material has been destroyed.
What are some of the advantages and disadvantages of this type of vaccine?
- Advantages:
- Well-established technology
- Suitable for people with compromised immune systems
- No live components, so no risk of the vaccine triggering disease
- Relatively simple to manufacture
- Relatively stable
- Disadvantages
- Booster shots may be required
Are there other vaccines of this type available in Canada?
- Yes, including all MMR and MMRV vaccines.
Are there COVID-19 vaccines of this type approved by Health Canada?
- No. There are no COVID-19 vaccines of this type approved by Health Canada at this time.
How do these vaccines work?
- Live-attenuated vaccines use a form of the COVID-19 virus that has been weakened in the laboratory, which can still grow and replicate, but causes mild or no illness.
- Because these are live COVID-19 viruses, they are able to infect human cells, and the human immune system can respond to these viruses almost as well as it does to the “wild-type” virus.
- The weakened virus enters human cells, and provides instructions so that cells make specific COVID-19 proteins.
- The immune system learns to recognize these proteins and develops antibodies and white blood cells against them, which provides immunity against COVID-19 in the future.
Are these “whole virus” vaccines?
- Yes, but the virus has been weakened so that it only produces mild or no illness.
Can these vaccines cause COVID-19 disease?
- Yes. In very rare cases, the live-attenuated virus may mutate and revert back to a more pathogenic form.
What are some of the advantages and disadvantages of this type of vaccine?
- Advantages:
- Immune response is strong as it involves B cells and T cells
- Well-established technology
- Relatively simple to manufacture
- Disadvantages:
- Unsuitable for people with compromised immune systems
- May trigger disease in very rare cases
- Relatively temperature sensitive, so careful storage necessary
Adapted from:
There are four types of COVID-19 vaccines: here’s how they work (GAVI, 2021).
Understanding How COVID-19 Vaccines Work (CDC, January 13, 2021).
Draft landscape and tracker of COVID-19 candidate vaccines (WHO, 2021).
Genetic engineering strategies for construction of multivalent chimeric VLPs vaccines (Expert Rev Vaccines, March 17, 2020)
Pfizer-BioNTech mRNA vaccine
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Clinical trial details
Enrollment
- > 45,000 participants across three studies
- Note that there were three separate studies, and within each study some participants were excluded from efficacy and safety analyses. Therefore, not all statistics are based on the total number of participants in a given age group. This can contribute to slightly different statistics being reported by different sources.
- For the number of patients in each subset, see Product monograph, including patient medication information: Pfizer-BioNTech COVID-19 vaccine (November 19, 2021).
Participant Demographics
- 2,260 were 12-15 years old
- 1,518 were 5-<12 years old
- Were of diverse racial and ethnic backgrounds:
- Among participants ≥12 years of age, approximately 83% were White, 9% were Black or African American, 27% were Hispanic/Latino, 4% were Asian, 0.2% were Native Hawaiian or other Pacific Islander, 0.6% were American Indian/Alaska Native, and 2% were multiracial
- Among participants 5-<12 years of age, 79.3% were White, 5.9% were Black or African American, 21.0% were Hispanic/Latino, 5.9% were Asian, and 0.8% were American Indian/Alaska Native
- Participants with pre-existing stable disease were included (disease not requiring significant change in therapy or hospitalization for worsening disease during the 6 weeks before enrolment)
- Participants with known stable infection were included, including those with HIV, hepatitis B, and hepatitis C virus
Efficacy
- 90.7% (95% CI: 67.7%, 98.3%) in those 5-<12 years of age
- 100.0% (95% CI: 78.1%, 100.0%) in those 12-15 years of age
- 91.1% (95% CI: 88.8%, 93.0%) in those ≥16 years of age
Serious side effects
- In participants >55 years old, serious adverse events were reported in 1.8% of vaccine recipients and 1.7% of placebo recipients.
- In participants 16-55 years old, serious adverse events were reported in 0.8% of vaccine recipients and 0.9% of placebo recipients.
- In participants 12-15 years old, serious adverse events were reported in 0.4% of vaccine recipients and 0.2% of placebo recipients.
- In participants 5-<12 years old, serious adverse events were reported in 0.1% of vaccine recipients and 0.1% of placebo recipients.
Non-serious side effects
- Side effects observed during the clinical trials were typically mild, commonly reported side effects of vaccines and do not pose a risk to health. Overall, solicited side effects were more frequent in vaccine recipients compared to placebo, more frequent after the second dose compared to the first, and more frequent in adults 18 to 55 years of age than in those 56 years of age and above.
Most frequently reported adverse reactions in subjects 5-<12 years of age:
- Very common side effects (may affect more than 1 in 10 people):
- Pain at injection site: 84.3% (vs. 29.5-31.3% in placebo)*
- Fatigue: 51.7% (vs. 24.3-31.3% in placebo)*
- Headache: 38.2% (vs. 18.6-24.1% in placebo)*
- Injection site redness: 26.4% (vs. 5.4-5.7% in placebo)*
- Injection site swelling: 20.4% (vs. 2.7% in placebo)
- Muscle pain: 17.5% (vs. 6.8-7.4% in placebo)
- Chills: 12.4% (vs. 4.3-4.7% in placebo)*
- Fever: 8.3% (vs. 1.2-1.3% in placebo)*
- Uncommon side effects (may affect up to 1 in 100 people):
- Enlarged lymph nodes
- Nausea
- Rash
- Malaise
- Decreased appetite
Most frequently reported adverse reactions in subjects ≥16 years of age:
- Very common side effects (may affect more than 1 in 10 people):
- Pain at injection site: 84.3% (vs. 11.6-14.2% in placebo)*
- Fatigue: 64.7% (vs. 22.9-33.0% in placebo)*
- Headache: 57.1% (vs. 24.3-33.5% in placebo)*
- Muscle pain: 40.2% (vs. 8.8-11.3% in placebo)
- Chills: 34.7% (vs. 4.2-6.8% in placebo)*
- Joint pain: 25.0% (vs. 5.5-5.8% in placebo)*
- Fever: 15.2% (vs. 0.4-0.9% in placebo)*
- Injection site swelling: 11.1% (vs. 0.2-0.6% in placebo)*
- Injection site redness: 9.9% (vs. 0.7-1.0% in placebo)*
- Uncommon side effects (may affect up to 1 in 100 people):
- Enlarged lymph nodes
- Nausea
- Malaise
- Weakness
- Decreased appetite
- Excessive sweating
- Lethargy
- Night sweats
Most frequently reported adverse reactions in subjects 12-15 years of age:
- Very common side effects (may affect more than 1 in 10 people):
- Pain at injection site: 90.5% (vs. 17.9-23.3% in placebo)*
- Fatigue: 77.5% (vs. 24.5-40.6% in placebo)*
- Headache: 75.5% (vs. 24.4-35.1% in placebo)*
- Muscle pain:42.2% (vs. 8.3-13.1% in placebo)
- Chills: 49.2% (vs. 6.8-9.7% in placebo)*
- Joint pain: 20.2% (vs. 4.7-6.8% in placebo)*
- Fever: 24.3% (vs. 0.6-1.1% in placebo)*
- Uncommon side effects (may affect up to 1 in 100 people):
- Enlarged lymph nodes
- Nausea
Contraindications and precautions
The Pfizer-BioNTech COVID-19 vaccine is contraindicated for:
- Individuals with a history of anaphylaxis after previous administration of the vaccine.
- Persons with proven immediate or anaphylactic hypersensitivity to any component of the vaccine or its container, including polyethylene glycol.
- Vaccination should be deferred in symptomatic individuals with confirmed or suspected SARS-CoV-2 infection, or those with symptoms of COVID-19. To minimize the risk of COVID-19 transmission, symptomatic individuals who arrive at an immunization clinic should be instructed to follow current local public health measures and be encouraged to get tested.
- Acutely ill individuals, as a precautionary measure.
- Individuals outside the authorized age group (< 5).
Precautions should be taken with:
- Patients who have a bleeding problem, bruise easily or use a blood-thinning medication.
- Patients with a history of fainting. Procedures should be in place to prevent injury from fainting and manage syncopal reactions.
- Individuals who have experienced a serious allergic reaction, including anaphylaxis, to another vaccine, drug or food, should talk to their health professional before receiving the vaccine.
- Patients who are pregnant or breastfeeding. See Special Populations.
- Patients who are immunocompromised, due to disease or treatment. See Special populations.
- Patients with suspected hypersensitivity or non-anaphylactic allergy to COVID-19 vaccine components. Consultation with an allergist is advised prior to vaccination.
- Patients with a history of myocarditis or pericarditis. See Rare vaccine adverse events .
Vaccine ingredients
Nucleic Acids
- mRNA
This is the active ingredient of the vaccine. It contains the instructions your body needs to build antibodies to help protect you against COVID-19.
Lipids
- ALC-0315 = ((4-hydroxybutyl)azanediyl)bis(hexane-6,1-diyl)bis(2-hexyldecanoate)
- ALC-0159 = 2-[(polyethylene glycol)-2000]-N,N-ditetradecylacetamide*
- 1,2-Distearoyl-sn-glycero-3-phosphocholine
- Cholesterol
These ingredients are lipids, a type of fat that forms a protective shell around the active ingredient, mRNA, and allows it to “slide” into cells so it can work.
Salts and Acid Stabilizers
- Dibasic sodium phosphate dihydrate (Acid Stabilizer)**
- Monobasic potassium phosphate (Salt)**
- Potassium chloride (Salt)
- Sodium chloride (Salt)
- Tromethamine (Acid stabilizer)***
- Tromethamine hydrochloride (Acid stabilizer)***
These ingredients are used as stabilizers for the vaccine to help maintain its pH close to that of a person’s body.
Sugar
- Sucrose
Sucrose is a type of sugar that is used as a stabilizer to help the vaccine particles keep their shape when they are frozen.
Water
- Water for injection
Water is used to mix the vaccine ingredients into a liquid that can be injected into the body.
See COVID-19 Vaccine Administration (MOH, October 20, 2021) for additional details.
Moderna mRNA vaccine
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The Moderna COVID-19 vaccine showed 94.1% efficacy in preventing SARS-CoV-2 infection and is used both for preventing the occurrence of COVID-19 infection and diminishing the severity of the infection. For information on preparation, administration, storage, stability and disposal, see Vaccine administration.
Updated Clinical trial details
Enrollment
- 30,351 participants (15,181 receiving vaccine and 15,170 receiving placebo) in trial of 18+
- 3,726 participants (2,486 receiving vaccine and 1,240 receiving placebo) in trial of children 12-17
- 4,002 participants (3,007 receiving vaccine and 995 receiving placebo) in trial of children 6-11
- 6,388 participants (4,560 receiving two doses of vaccine and 1,499 receiving two doses of placebo) in trial of children 6 months – 5 years
- Note that some participants were excluded from efficacy and safety analyses, therefore not all statistics are based on the total number of participants in a given age group. This can contribute to slightly different statistics being reported by different sources.
- For the number of patients in each subset, see the Moderna COVID-19 vaccine product monograph (Moderna, March 17, 2022).
Participant demographics
- Within the trial in adults 18+
- 25.3% of the adult trial were 65 years of age or older
- 52.6% were male, 47.4% were female
- 36.2% were from communities of colour
- 22.6% had at least one high risk condition, including: chronic lung disease, moderate to severe asthma, significant cardiac disease, severe obesity, diabetes, liver disease, and HIV infection
- Within the trial in children 12-17
- 51.4% were male, 48.6% were female
- 11.6% were Hispanic or Latino, 83.9% were White, 3.4% were African American, 5.9% were Asian, 0.5% were American Indian or Alaska Native, <0.1% were Native Hawaiian or Pacific Islander, 1.0% were other races, and 4.5% were multiracial
- Within the trial in children 6-11
- 50.8% were female and 49.2% male
- 18.5% were Hispanic or Latino, 65.6% were White, 10.0% were African American, 9.9% were Asian, 0.4% were American Indian or Alaska Native, <0.1% were Native Hawaiian or Pacific Islander, 2.1% were other races and 10.6% were multiracial
- Within the trial in children 6 months – 5 years of age
- 50.9% were male and 49.1% female
- 13.9% were Hispanic or Latino, 77.4% were White, 4.0% were African American, 5.6% were Asian, 0.3% were American Indian or Alaska Native, 0.2% were Native Hawaiian or Pacific Islander, 1.5% were other races, and 10.5% were multiracial
Efficacy
- 94.1% efficacy was observed in participants 18+
- 86.4% efficacy was observed in participants 65+
- 100% efficacy was observed in children 12-17
- Efficacy in children 6-11 has not been reported, due to too few COVID-19 cases occurring in the clinical trial (in both the placebo and vaccine groups)
- However, laboratory-based immunogenicity studies suggest that the vaccine is as effective in trial participants 6 to 11 years old as in young adults (18 to 25 years old)
- 37% efficacy was observed in children 2-5 years old
- 51% efficacy was observed in children 6-23 months
Serious side effects
- Overall, serious adverse events were reported in:
- 1.0% of vaccine recipients and 1.0% of placebo recipients aged 18+
- 0.2% of vaccine recipients and 0.2% of placebo recipients aged 12-17
- <0.1% of vaccine recipients and 0% of placebo recipients aged 6-11
- <0.3% of vaccine recipients and 0.2% of placebo recipients aged 2-5
- <0.9% of vaccine recipients and 0.2% of placebo recipients aged 6-23 months
Non-serious side effects
- Side effects observed during the clinical trials were typically mild, commonly reported side effects of vaccines and do not pose a risk to health. Across all age groups, solicited side effects were more frequent in vaccine recipients compared to placebo and more frequent after the second dose compared to the first.
Most commonly reported side effects (adults 18+):
- Pain at injection site: 88.4% (vs.17.0% in placebo)*
- Fatigue: 68.5% (vs. 36.1% in placebo)
- Headache: 63.0% (vs. 36.5% in placebo)
- Myalgia: 59.6% (vs. 20.1% in placebo)
- Arthralgia: 44.8% (vs.17.2% in placebo)
- Chills: 43.4% (vs. 9.5% in placebo)
- Fever: 14.8% (vs. 0.6% in placebo)
- Swollen lymph nodes: 14.0% (vs 3.9% in placebo)*
Most commonly reported side effects (children 6-11):
- Pain at injection site: 94.8% (vs. 49.5% in placebo)*
- Fatigue: 64.5% (vs. 34.6% in placebo)*
- Headache: 54.3% (vs. 28.4% in placebo)*
- Myalgia: 28.2% (vs. 10.8% in placebo)*
- Arthralgia: 16.1% (vs.8.7% in placebo)*
- Chills: 30.3% (vs. 7.6% in placebo)*
- Fever: 23.9% (vs. 2.0% in placebo)*
- Nausea/vomiting: 24.0% (vs. 10.0% in placebo)*
Most commonly reported side effects (children 6-23 months):
- Pain at injection site: 46.2% (vs. 25.7% in placebo)*
- Erythema: 13.5% (vs. 3.8% in placebo)*
- Swelling: 15.2% (vs. 2.1% in placebo)*
- Axillary (or groin) swelling or tenderness: 93% (vs. 5.3% in placebo)*
- Fever: 14.6% (vs. 8.4% in placebo)*
- Irritability/crying: 64.3% (vs. 58.5% in placebo)*
- Sleepiness: 35.1% (vs. 33.3% in placebo)*
- Loss of appetite: 32.1% (vs. 25.1% in placebo)*
Most commonly reported side effects (children 12-17):
- Pain at injection site: 92.4% (vs. 30.3% in placebo)*
- Fatigue: 67.8% (vs. 28.9% in placebo)*
- Headache: 70.2% (vs. 30.3% in placebo)*
- Myalgia: 46.6% (vs. 12.5% in placebo)*
- Arthralgia: 28.9% (vs.9.3% in placebo)*
- Chills: 43.0% (vs. 8.0% in placebo)*
- Fever: 12.2% (vs. 1.0% in placebo)*
- Nausea/vomiting: 23.9% (vs. 8.7% in placebo)*
Most commonly reported side effects (children 2-5 years):
- Pain: 71.4% (vs. 41.2% in placebo)*
- Fever: 16.0% (vs. 4.5% in placebo)**
- Headache: 15.7% (vs. 8.1% in placebo)**
- Irritability/crying: 54.3% (vs. 44.8% in placebo)***
- Fatigue: 48.4% (vs. 29.4% in placebo)**
- Myalgia: 15.7% (vs. 7.5% in placebo)**
- Arthralgia: 8.5% (vs. 4.5% in placebo)**
- Loss of appetite: 30.5% (vs. 20.9% in placebo)***
- Nausea/vomiting: 9.8% (vs. 4.8% in placebo)**
- Chills: 12.4% (vs. 4.9% in placebo)**
- Erythema: 8.8% (vs. 1.6% in placebo)*
- Swelling: 8.2% (vs. 1.1% in placebo)*
- Axillary (or groin) swelling or tenderness: 9.1% (vs. 3.2% in placebo)*
- Use of antipyretic or analgesic medications: 27.2% (vs. 10.9% in placebo)*
Contraindications and precautions
The Moderna COVID-19 vaccine is contraindicated for:
- Individuals with a history of anaphylaxis after previous administration of the vaccine.
- Individuals with proven immediate or anaphylactic hypersensitivity to any component of the vaccine or its container, including polyethylene glycol.
- Individuals who have received another vaccine (not a Moderna COVID-19 vaccine) in the past 14 days.
- Individuals outside of the authorized age group (< 6 months of age).
- Symptomatic individuals with confirmed or suspected SARS-CoV-2 infection, or those with symptoms of COVID-19. To minimize the risk of COVID-19 transmission, symptomatic individuals who arrive at an immunization clinic should be instructed to follow current local public health measures and be encouraged to get tested.
Precautions should be taken with:
- Patients who have a bleeding problem, bruise easily or use a blood-thinning medication.
- Patients with a history of fainting. Procedures should be in place to prevent injury from fainting and manage syncopal reactions.
- Individuals who have experienced a serious allergic reaction, including anaphylaxis, to another vaccine, drug or food, should talk to their health professional before receiving the vaccine.
- Patients who are pregnant or breastfeeding. See Pregnant and breastfeeding women.
- Patients who are immunocompromised, due to disease or treatment. See Immunocompromised populations.
- Patients with suspected hypersensitivity or non-anaphylactic allergy to COVID-19 vaccine components. Consultation with an allergist is advised prior to vaccination.
- Patients with a history of myocarditis or pericarditis. See Vaccine adverse events.
- Patients with severe febrile illness or severe acute infection. Consideration should be given to postponing immunization until the illness or infection has improved.
Vaccine ingredients
Nucleic acid
- mRNA
This is the active ingredient of the vaccine. It contains the instructions your body needs to build antibodies to help protect you against COVID-19.
Lipids
- Lipid SM-102
- PEG2000 DMG (1,2-dimyristoyl-rac-glycerol,methoxy-polyethyleneglycol)*
- 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC)
- Cholesterol
These ingredients are lipids, a type of fat that forms a protective shell around the active ingredient, mRNA, and allows it to “slide” into cells so it can work.
Salts, Acids, and Acid Stabilizers
- Sodium acetate (Salt)
- Acetic acid (Acid)
- Trometamol (Acid stabilizer)
- Trometamol hydrochloride (Acid stabilizer)
These ingredients are used as stabilizers for the vaccine to help maintain its pH close to that of a person’s body.
Sugar
- Sucrose
Sucrose is a type of sugar that is used as a stabilizer to help the vaccine particles keep their shape when they are frozen
Water
- Water for injection
Water is used to mix the vaccine ingredients into a liquid that can be injected into the body
See Product Monograph, including patient medication information: Moderna COVID-19 Vaccine for more details.
Janssen (Johnson & Johnson) viral vector vaccine New
Jump to:
The Janssen vaccine showed 66.1% efficacy in preventing SARS-CoV-2 infection and is used both for preventing the occurrence of COVID-19 infection and diminishing the severity of the infection. For information on preparation, administration, storage, stability and disposal, see Vaccine administration.
Clinical trial details
Enrollment
- 44,325 total participants
- Note that some participants were excluded from efficacy and safety analyses, therefore not all statistics are based on the total number of participants (44,325). This can contribute to slightly different statistics being reported by different sources.
- 39,321 total participants were included in the primary efficacy analysis (19,630 in the Janssen COVID-19 Vaccine group and the 19,691 in the placebo group)
- For the number of patients in each subset, see Janssen COVID-19 Product Monograph (Janssen, April 23, 2021).
Participant demographics
Janssen COVID-19 Vaccine Group
- 20.3% were 65 years of age or older
- Were of diverse racial and ethnic backgrounds:
- White (62.1%)
- Black or African American (17.2%)
- American Indian or Alaska native (8.4%)
- Asian (3.7%)
- Native Hawaiian or other Pacific Islander (0.3%)
- Hispanic or Latino (44.8%)
- Multiracial (5.3%)
- 39.9% had ≥1 comorbidities* at baseline that increase the risk of progression to severe/critical COVID-19.
Placebo Group
- 20.4% were 65 years of age or older
- Were of diverse racial and ethnic backgrounds:
- White (62%)
- Black or African American (17.2%)
- American Indian or Alaska native (8.3%)
- Asian (3.4%)
- Native Hawaiian or other Pacific Islander (0.2%)
- Hispanic or Latino (45.4%)
- Multiracial (5.5%)
- 40% had ≥1 comorbidities* at baseline that increase the risk of progression to severe/critical COVID-19.
*Obesity defined as BMI ≥30 kg/m2 (27.5%), hypertension (10.3%), type 2 diabetes (7.2%), stable/well-controlled HIV infection (2.5%), serious heart conditions (2.4%), asthma (1.3%) and in ≤1% of individuals: cancer, cerebrovascular disease, chronic kidney disease, chronic obstructive pulmonary disease, cystic fibrosis, immunocompromised state (weakened immune system) from blood or organ transplant, liver disease, neurologic conditions, pulmonary fibrosis, sickle cell disease, thalassemia and type 1 diabetes, regardless of age.
Time followed
At the time of the final primary efficacy analysis (cut-off date of January 22, 2021), participants had been followed for symptomatic COVID 19 disease for a median of 8 weeks post-vaccination, corresponding to 3,143.7 person years for the Janssen COVID-19 Vaccine and 3,146.7 person years in the placebo group.
Protection
As with any vaccine, vaccination with the Janssen COVID-19 Vaccine may not protect all vaccinated individuals. Even after you have had the vaccine, continue to follow the recommendations of local public health officials to prevent spread of COVID-19.
Efficacy
Vaccine efficacy for the co-primary endpoints against moderate to severe/critical COVID-19 in individuals who were seronegative or who had an unknown serostatus at baseline was 66.9% at least 14 days after vaccination and 66.1% at least 28 days after vaccination. Vaccine efficacy results against moderate to severe/critical COVID-19 are presented in Table 7 in the Janssen COVID-19 Product Monograph (Janssen, April 23, 2021).
Serious side effects
Serious adverse events were experienced by 0.4% of subjects in the vaccine group and 0.6% of subjects in the placebo group. When COVID-19-related SAEs were excluded, 0.4% of participants in both the vaccine group and the placebo group reported an SAE.
Non-serious side effects
Solicited adverse reactions were generally more common in younger than in older age groups. Most adverse reactions occurred within 2 days following vaccination, were mild to moderate in severity, and of short duration (2 to 3 days). Most of the unsolicited adverse events were of Grade 1 or Grade 2 severity, with 0.6% of participants in each group reporting an unsolicited AE of Grade 3 severity. The most common unsolicited AEs occurring within 28 days after vaccination were predominantly reactogenicity events, some of which overlapped with the solicited AEs.
Most frequently reported adverse reactions in subjects 18-59 years of age:
- Injection site pain: 58.6% (vs. 17.4% in placebo group)
- Injection site erythema: 9.0% (vs. 4.3% in placebo group)
- Injection site swelling: 7.0% (vs. 1.6% in placebo group)
- Headache: 44.4% (vs. 24.8% in placebo group)
- Fatigue: 43.8% (vs. 22.0% in placebo group)
- Myalgia: 39.1% (vs. 12.1% in placebo group)
- Nausea: 15.5% (vs. 8.9% in placebo group)
- Fever: 12.8% (vs. 0.7% in placebo group)
Most frequently reported adverse reactions in subjects ≥ 60 years of age:
- Injection site pain: 33.3% (vs. 15.6% in placebo group)
- Injection site erythema: 4.6% (vs. 3.2% in placebo group)
- Injection site swelling: 2.7% (vs. 1.6% in placebo group)
- Headache: 30.4% (vs. 22.1% in placebo group)
- Fatigue: 29.7% (vs. 20.8% in placebo group)
- Myalgia: 24.0% (vs. 13.7% in placebo group)
- Nausea: 12.3% (vs. 10.8% in placebo group)
- Fever: 3.1% (vs. 0.5% in placebo group)
Contraindications and precautions
The Janssen vaccine is contraindicated for:
- Individuals who have had a severe allergic reaction to any of the medicinal ingredients or any of the other ingredients in this vaccine or any other adenovirus-based vaccines.
- Vaccination should be deferred in symptomatic individuals with confirmed or suspected SARS-CoV-2 infection, or those with symptoms of COVID-19. To minimize the risk of COVID-19 transmission, symptomatic individuals who arrive at an immunization clinic should be instructed to follow current local public health measures and be encouraged to get tested.
- Individuals who have received another vaccine in the past 14 days.
- Individuals outside of the authorized age group (< 18).
Precautions should be taken with:
- Patients who have a bleeding problem, bruise easily or use a blood-thinning medication.
- Patients with a history of fainting. Procedures should be in place to prevent injury from fainting and manage syncopal reactions.
- Individuals who have experienced a severe allergic reaction, including anaphylaxis after any other vaccine injection.
- Individuals who have experienced a previous cerebral venous sinus thrombosis (CVST) or heparin-induced thrombocytopenia (HIT).
- Patients who are pregnant or breastfeeding. See Pregnant and breastfeeding women.
- Patients who are immunocompromised, due to disease or treatment. See Immunocompromised populations
Vaccine ingredients
Viral vector
- Adenovirus type 26 (recombinant, replication-incompetent human adenovirus)
This is the active ingredient of the vaccine. It is a harmless virus that causes the common cold, which has been genetically modified to contain the instructions your body needs to build antibodies against COVID-19. It has also been modified so that it does not cause infection.
Alcohol
- Ethanol
This ingredient helps to keep the adenovirus from breaking down.
Acid and base stabilizers
- Citric acid monohydrate (mild acid)
- Trisodium citrate dihydrate (mild base)
These ingredients are used to help balance the pH of the vaccine so it is close to that of a person’s body.
Emulsifier
- Polysorbate 80
This ingredient, which is commonly found in foods and cosmetics, helps to keep the oil-based and water-based ingredients from separating.
Salt
- Sodium chloride; AND
- Sodium hydroxide (a base) and hydrochloric acid (an acid), which combine in the vial to make water and sodium chloride (table salt)
Sodium chloride is also known as table salt, and is used to help balance the salt levels in the vaccine so they are close to that of a person’s body.
Sugar
- 2-hydroxypropyl-β-cyclodextrin (HBCD)
This ingredient helps to keep the vaccine a liquid.
Water
- Water for injection
Water is used to mix the vaccine ingredients into a liquid that can be injected into the body.
See Product Monograph, including patient medication information: Janssen COVID-19 Vaccine for more details.
Oxford-AstraZeneca viral vector vaccine
Jump to:
The AstraZeneca vaccine showed 59.5% efficacy in preventing SARS-CoV-2 infection and is used both for preventing the occurrence of COVID-19 infection and diminishing the severity of the infection. For information on preparation, administration, storage, stability and disposal, see Vaccine administration.
Clinical trial details
Enrollment
Study COV002 (United Kingdom)
- 7,548 total participants (3,744 receiving the AstraZeneca COVID-19 vaccine, 3,804 receiving two doses of a meningococcal vaccine control)
- For the number of patients in each subset, see AstraZeneca COVID-19 Product Monograph (AstraZeneca, April 23, 2021).
Study COV003 (Brazil)
- 4,088 total participants (2,063 receiving the AstraZeneca COVID-19 vaccine, 2,025 receiving meningococcal vaccine followed by saline placebo control)
- For the number of patients in each subset, see AstraZeneca COVID-19 Product Monograph (AstraZeneca, April 23, 2021)
Participant demographics
Study COV002 (United Kingdom)
- 7.4% were 65 years of age or older
- 7.55% were from communities of colour
- 35.9% had 1 or more of the following comorbidities at baseline: BMI 30kg/m2 or higher, cardiovascular disorder, respiratory disease or diabetes
Study COV003 (Brazil)
- 2.5% were 65 years of age or older
- 33.5% were from communities of colour
- 36.5% had 1 or more of the following comorbidities at baseline at baseline: BMI 30kg/m2 or higher, cardiovascular disorder, respiratory disease or diabetes
Time followed
At the time of the interim primary efficacy analysis, participants had been followed for symptomatic COVID-19 disease for a median of 63 days (range: 16-94 days) after the second dose, corresponding to exposure of 921 person-years in the AstraZeneca COVID-19 Vaccine and 925 person-years in the control group.
Protection
Individuals may not be optimally protected until after receiving the second dose of the vaccine.
Efficacy
- In participants who received two standard doses of the vaccine (SD/SD) or the corresponding control, vaccine efficacy from 15 days-post second dose was 62.1%.
- Based on an updated analysis (data cut-off December 7, 2020), vaccine efficacy was 59.5% in participants who received two standard doses with the second dose administered 4 to 12 weeks after the first dose.
Serious side effects
Serious adverse events were experienced by 0.7% of subjects in the AstraZeneca COVID-19 Vaccine group and 0.8% of subjects in the control group.
Non-serious side effects
In clinical studies with the vaccine, most side-effects were mild-to-moderate and resolved within a few days. When compared with the first dose, adverse reactions reported after the second dose were milder and reported less frequently. Reactogenicity was generally milder and reported less frequently in older adults (≥65 years old).
Most frequently reported adverse reactions in subjects 18 years of age and older:
- Injection site tenderness: 75.3% (vs. 18.4-78.7% in placebo)*
- Injection site pain: 54.2% (vs. 4.9-37.1% in placebo)*
- Fatigue: 62.3% (vs. 21.1-46.2% in placebo)*
- Headache: 57.5% (vs. 14.3-42.3% in placebo)*
- Myalgia: 48.6% (vs. 8.5-23.8% in placebo)*
- Malaise: 44.2% (vs. 6.7-18.5% in placebo)*
- Fever: 7.95% (vs. 0-0.6% in placebo)*
- Feverishness: 33.6% (vs. 3.1-9.9% in placebo)*
- Chills: 31.9% (vs. 2.7-7.6% in placebo)*
- Arthralgia: 27.0% (vs. 6.6-9.0% in placebo)*
- Nausea: 21.9% (vs. 3.1-12.1% in placebo)*
Contraindications and precautions
The AstraZeneca vaccine is contraindicated for:
- Individuals who have had an allergic reaction to a previous dose of the vaccine.
- Individuals who have had a severe allergic reaction to any of the medicinal ingredients or any of the other ingredients in this vaccine.
- Individuals who have experienced major venous or arterial thrombosis with thrombocytopenia following a previous dose of the vaccine.
- Vaccination should be deferred in symptomatic individuals with confirmed or suspected SARS-CoV-2 infection, or those with symptoms of COVID-19. To minimize the risk of COVID-19 transmission, symptomatic individuals who arrive at an immunization clinic should be instructed to follow current local public health measures and be encouraged to get tested.
- Individuals who have received another vaccine (not a AstraZeneca COVID-19 vaccine) in the past 14 days.
- Individuals outside of the authorized age group (< 18).
Precautions should be taken with:
- Patients who have a bleeding problem, bruise easily or use a blood-thinning medication.
- Patients with a history of fainting. Procedures should be in place to prevent injury from fainting and manage syncopal reactions.
- Individuals who have experienced a severe allergic reaction, including anaphylaxis after any other vaccine injection.
- Individuals who have experienced a previous cerebral venous sinus thrombosis (CVST) or heparin-induced thrombocytopenia (HIT). See AstraZeneca safety.
- Patients who are pregnant or breastfeeding. See Pregnant and breastfeeding women.
- Patients who are immunocompromised, due to disease or treatment. See Immunocompromised populations
Vaccine ingredients
Viral vector
- ChAdOx1-S (recombinant, replication-incompetent chimpanzee adenovirus)
This is the active ingredient of the vaccine. It is a harmless virus that causes the common cold in chimpanzees, which has been genetically modified to contain the instructions your body needs to build antibodies against COVID-19. It has also been modified so that it does not cause infection.
Stabilizer
- Magnesium chloride hexahydrate (salt)
- Disodium edetate dihydrate (EDTA)
- Ethanol (alcohol)
- Sucrose (sugar)
These ingredients are stabilizers that are used to prevent clump formation in the vaccine.
Amino acid (and amino acid salt)
- L-Histidine
- L-Histidine hydrochloride monohydrate
These ingredients are used to help balance the pH of the vaccine so it is close to that of a person’s body.
Emulsifier
- Polysorbate 80
This ingredient, which is commonly found in foods and cosmetics, helps to keep the oil-based and water-based ingredients from separating.
Salt
- Sodium chloride
This ingredient, also known as table salt, is used to help balance the salt levels in the vaccine so they are close to that of a person’s body.
Water
- Water for injection
Water is used to mix the vaccine ingredients into a liquid that can be injected into the body.
Novavax protein subunit vaccine
Jump To:
The Novavax COVID-19 vaccine showed approximately 90% efficacy in preventing SARS-CoV-2 infection (89.7% in one study and 90.4% in second study), and is used both for preventing the occurrence of COVID-19 infection and diminishing the severity of the infection. For information on preparation, administration, storage, stability and disposal, see Vaccine administration.
Clinical trial details
Enrollment
- > 45,000 participants across two studies
- Study 1 (2019nCoV-301) conducted in North America
- Study 2 (2019nCoV-302) conducted in the United Kingdom
- Note that there are two separate studies, and within each study some participants were excluded from efficacy and safety analyses. Therefore, not all statistics are based on the total number of participants in a given age group. This can contribute to slightly different statistics being reported by different sources.
- For the number of patients in each subset, see Product monograph, including patient medication information: Nuvaxovid COVID-19 vaccine (February 17, 2022).
Participant demographics
- In both studies, demographic and baseline characteristics were balanced amongst participants who received the vaccine and those who received placebo
- Participants in Study 1:
- 88% were 18-64 years old and 12% were >64 years old
- 76% were White, 11% were Black or African American, 6% were American Indian (including Native Americans) or Alaskan Native, 4% were Asian, and 22% were Hispanic or Latino
- 95% had at least one pre-existing comorbidity or lifestyle characteristic associated with an increased risk of severe COVID-19
- Excluded those who were significantly immunocompromised due to immunodeficiency disease, on chemotherapy, received chronic immunosuppressive therapy or received immunoglobulin or blood-derived products within 90 days, were pregnant, or had a history of laboratory-confirmed diagnosed COVID-19
- Participants in Study 2:
- 72% were 18-64 years old and 28% were >64 years old
- 95% were White, 3% were Asian, 1.0% were multiple races, 0.4% were Black or African American, 1% were Hispanic or Latino
- 45% had at least one comorbid condition
- Excluded those who were significantly immunocompromised due to immunodeficiency disease, current diagnosis or treatment for cancer, autoimmune disease/condition, received chronic immunosuppressive therapy or received immunoglobulin or blood-derived products within 90 days, bleeding disorder or continuous use of anticoagulants, history of allergic reactions and/or anaphylaxis, were pregnant, or had a history of laboratory -confirmed diagnosed COVID-19.
Efficacy
- 90.4% (95% CI: 82.9%, 94.6%) in Trial #1
- 89.7% (95% CI: 80.2%, 94.6%) in Trial #2
Serious side effects
- Overall, serious side effects were uncommon, with a higher incidence rate in participants who received placebo than those who received the vaccine (4.09 vs 3.82 events, per 100 person-years).
- A slightly higher incidence rate occurred among participants ≥ 65 years of age compared to those 18-64.
Non-serious side effects
- Side effects observed during the clinical trials were typically mild, commonly reported side effects of vaccines and do not pose a risk to health. Overall, solicited side effects were more frequent in vaccine recipients compared to placebo, more frequent after the second dose compared to the first, and more frequent in adults 18 to 64 years of age than in those 65 years of age and above.
Most frequently reported adverse reactions:
- Very common side effects:
- Pain at injection site: 56% (vs. 7.7-12.7% in placebo)*
- Tenderness at injection site: 68% (vs 9.6-15.4% in placebo)*
- Fatigue: 45% (vs. 13.9-20.3% in placebo)*
- Headache: 41% (vs. 12.8-22.3% in placebo)*
- Muscle pain: 44% (vs. 9.4-12.6% in placebo)*
- Malaise: 35% (vs. 7.6-10.7% in placebo)*
- Nausea or vomiting: 11% (vs. 2.6-5.7% in placebo)*
- Joint pain: 20% (vs. 5.6-6.7% in placebo)*
- Uncommon side effects:
- Fever
- Chills
- Injection site swelling
- Injection site erythema
Contraindications and precautions
Severe immediate allergic reactions (e.g., anaphylaxis) have not been reported following immunization with Novavax Nuvaxovid in the clinical trials. However, given the size of the clinical trials, rare and very rare side effects of the Novavax Nuvaxovid are not likely to have been identified at this time.
The Novavax vaccine is contraindicated for:
- An allergy to a component of a specific vaccine or its container, specifically Polysorbate 80.
- An allergic reaction to a previous dose of the vaccine.
- Have current symptoms that could be due to COVID-19. Consult a healthcare professional prior to receiving the vaccine.
- Individuals outside of the authorized age group (>18)
Precautions should be taken if patients:
- Have ever fainted following any needle injection
- Have a bleeding problem, bruise easily or use a blood thinning medication
- Have a high fever or severe infection
- Have any serious illness
- Your immune system does not work properly (immunodeficiency) or you are taking medicines that weaken the immune system (such as high-dose corticosteroids, immunosuppressants, or cancer medicines)
- Are pregnant, think you may be pregnant or plan to become pregnant
- Are breastfeeding or plan to breastfeed
- For those who have any allergies or previous problems following administration of Novavax, such as an allergic reaction or breathing problems, they should speak to their health professional prior to receiving Novavax.
Vaccine ingredients
Protein subunit
- SARS-CoV-2 recombinant spike (rS) protein (original [Wuhan] strain)
This is the active ingredient of the vaccine. It is a spike protein, made using moth cells, that causes your body to produce antibodies against COVID-19. The spike protein is harmless and does not cause COVID-19.
Adjuvant
- Matrix-M adjuvant (Quillaja saponaria sponnins fraction-A and fraction-C)
The adjuvant is an ingredient that helps stimulate an immune response to the vaccine. This Matrix-M adjuvant is composed of 40 nanometer particles based on saponin extracted from the Quillaja Saponaria Molina bark, also known as the soap bark tree.
Lipids
- Cholesterol
This ingredient is a lipid, a type of fat that forms a protective shell around the active ingredients and allows it to “slide” into cells so it can work.
Salts, acids, bases and stabilizers
- Disodium hydrogen phosphate dihydrate (mild base)
- Disodium hydrogen phosphate heptahydrate (acid stabilizer)
- Hydrochloric acid (acid)
- Potassium chloride (salt)
- Potassium dihydrogen phosphate (salt)
- Sodium chloride (salt)
- Sodium dihydrogen phosphate monohydrate (salt)
These ingredients are used to help balance the pH and salt levels of the vaccine so they are close to that of a person’s body.
Emulsifier
- Phosphatidylcholine
- Polysorbate 80
These ingredients, which are commonly found in foods and cosmetics, help to keep the oil-based and water-based ingredients from separating.
Water
- Water for injection
Water is used to mix the vaccine ingredients into a liquid that can be injected into the body.
Medicago virus-like particles vaccine
Jump to:
The Medicago COVID-19 vaccine showed approximately 70.1% efficacy in preventing SARS-CoV-2 infection, and is used both for preventing the occurrence of COVID-19 infection and diminishing the severity of the infection. The safety and efficacy of the Medicago COVID-19 vaccine has not been demonstrated in individuals under 18 years of age or over 64 years of age. For information on preparation, administration, storage, stability and disposal, see Vaccine administration.
Clinical trial details
Enrollment
- > 24,000 participants in one randomized, observer-blinded, placebo-controlled study
- Note that some participants were excluded from efficacy and safety analyses. Therefore, not all statistics are based on the total number of participants in a given age group. This can contribute to slightly different statistics being reported by different sources.
- For the number of patients in each subset, see Product monograph, including patient medication information: COVIFENZ COVID-19 vaccine (February 17, 2022)
Participant Demographics
- Demographic and baseline characteristics were balanced amongst participants who received the vaccine and those who received placebo
- 99.4% were 18 to 64 years old and 0.6% were aged 65 and older
- In the 18-64 year old group
- 50.1% were female
- 45% were from the Argentina, 31.8% from Brazil, 9.3% from USA, 6.7% from Mexico, 5.9% from Canada and 1.2% from Great Britain
- 88.9% were White, 6.3% were Black or African American, 1.8% were from multiple races, 1.2% were Asian, 0.5% did not report their race, 0.2% were American Indian (including Native Americans), 0.2% were Native Hawaiian or Other Pacific Islander and less than 0.1% were reported missing or other
- At least one pre-existing comorbidity or lifestyle characteristic associated with an increased risk of severe COVID-19 was present in 14.4% participants. Comorbidities included: Obesity (10.0%), Documented Hypertension (2.8%), Type 2 Diabetes (0.9%), Immunocompromised (0.4%), Chronic Obstructive Lung Disease (0.4%), Cardiovascular disease (0.3%), Asthma (0.2%)
Efficacy
- 71.0% (95% CI: 58.7, 80.0)
Serious side effects
- Serious adverse events were reported in 0.4% of vaccine recipients and 0.3% of placebo recipients.
Non-serious side effects
- Side effects observed during the clinical trials were typically mild, commonly reported side effects of vaccines and do not pose a risk to health. Overall, solicited side effects were more frequent in vaccine recipients compared to placebo, more frequent after the second dose compared to the first
Most frequently reported adverse reactions:
- Very common side effects:
- Pain at injection site: 92.5% (vs. 29.7-30.3% in placebo)*
- Headache: 68.5% (vs. 25.8-35.7% in placebo)*
- Muscle aches: 67.8% (vs. 16.9-21.2% in placebo)*
- Fatigue: 64.7% (vs. 21.6-28.5% in placebo)*
- Feeling of general discomfort: 63.8% (vs. 15.8-19.2% in placebo)*
- Chills: 46.7% (vs. 7.2-9.7% in placebo)*
- Joint aches: 40.0% (vs. 8.5-11.1% in placebo)*
- Swelling at injection site: 38.0% (vs. 2.9-3.1% in placebo)*
- Swelling in the neck: 22.2% (vs. 6.7-9.0% in placebo)*
- Erythema at injection site: 20.1% (vs. 2.1-2.9% in placebo)*
- Swelling in the axilla: 15.1% (vs. 1.9-3.4% in placebo)*
- Fever: 9.7% (vs. 0.5-0.9% in placebo)*
- Uncommon side effects (observed in vaccine and placebo recipients at very low frequencies):
- Nasal congestion
- Oropharyngeal pain
- Cough
- Catarrh
- Diarrhea
- Nausea
Contraindications and precautions
The Medicago vaccine is contraindicated in:
- Individuals who are hypersensitive to the active substance or to any ingredient in the formulation
- An allergic reaction to a previous dose of the vaccine.
- Have current symptoms that could be due to COVID-19. Consult a healthcare professional prior to receiving the vaccine.
- Individuals receiving anticoagulant therapy or those with a bleeding disorder that would contraindicate intramuscular injection unless the potential benefit clearly outweighs the risk of administration
- Individuals outside of the authorized age group (18 – 64)
Precautions should be taken if patients:
- Individuals who have history of confirmed anaphylaxis to plant materials
- Have ever fainted following any needle injection
- Have a bleeding problem, bruise easily or use a blood thinning medication
- Have a high fever or severe infection
- Have any serious illness
- Immune system does not work properly (immunodeficiency) or you are taking medicines that weaken the immune system (such as high-dose corticosteroids, immunosuppressants, or cancer medicines)
- Are pregnant, think they may be pregnant or plan to become pregnant
- Are breastfeeding or plan to breastfeed
- For those who have any allergies or previous problems following administration of COVID-19 vaccines, such as an allergic reaction or breathing problems, they should speak to their health professional prior to receiving the Medicago vaccine.
Adapted from:
Product Monograph (Government of Canada, February 24, 2022)
Vaccine ingredients
Virus-like particles
- Plant-based virus-like particles (VLP) of SARS-CoV-2 spike protein (original strain)
This is the active ingredient of the vaccine. It is a spike protein, made from plants, that looks like the SARS-CoV-2 virus and causes your body to produce antibodies and immune cells. The spike protein is harmless and does not cause COVID-19.
Adjuvant
- AS03 Adjuvant (manufactured by GlaxoSmithKline
The adjuvant is an ingredient that helps stimulate an immune response to the vaccine. This adjuvant contains naturally occurring molecules (squalene and vitamin E) plus an emulsifier (polysorbate 80) and phosphate buffered saline (salt).
Lipids
- Polyethylene glycol (trace amounts)
This ingredient is a lipid, a type of fat that forms a protective shell around the active ingredients and allows it to “slide” into cells so it can work.
Antibiotics
- Carbenicillin (trace amounts)
- Kanamycin (trace amounts)
These ingredients help minimize bacterial contamination during the initial manufacturing process. They are typically removed in subsequent vaccine manufacturing steps, but trace amounts can still be present.
Salts
- Potassium phosphate monobasic anhydrous
- Sodium chloride
- Sodium phosphate dibasic anhydrous
These ingredients are used to help balance the pH and salt levels of the vaccine so they are close to that of a person’s body.
Emulsifier
- Polysorbate 80
This ingredient, which is commonly found in foods and cosmetics, helps to keep the oil-based and water-based ingredients from separating.
Water
- Water for injection
Water is used to mix the vaccine ingredients into a liquid that can be injected into the body.
Patient resources
This is not an exhaustive list of COVID-19 patient-facing resources. These resources were selected as they meet key criteria identified by CEP’s partners, stakeholders and Information experts: authoritative sources, short formats, engaging design, multilingual translations, and focus on key messaging. To combat information overload, we are strictly curating this list to avoid redundancy. Additions, updates and substitutions will be made on a case-by-case basis according to alignment with selection criteria.
Comprehensive vaccine FAQs
- COVID-19 Vaccine (City of Hamilton): FAQs on safety and effectiveness of the COVID-19 vaccine, and links to resources simplifying the science of vaccines. Does include some Hamilton-specific information.
- COVID-19 Vaccine Fact Sheet (City of Toronto): Not limited to Toronto-specific information. Vaccine FAQs and info sheet on benefits, side effects, ingredients and allergies, as well as vaccinations while pregnant or breastfeeding, with health conditions, or with previous COVID-19 infection. See “COVID-19 Fact Sheet and Translations” section for short info sheet available in 32 languages including English, French, Spanish, Arabic, and Chinese.
Multilingual information
- 1-page vaccine bulletin on Moderna in 15 different languages including Amharic, Swahili, Somali, Tamil
- Video: Misinformation & Conspiracy Theories, with translation in American Sign Language
- What you need to know about the COVID-19 vaccine for Canada (PHAC): 2-page information sheet for Canadians on COVID-19 vaccines, including safety and efficacy, availability, prioritization, community immunity, cost and choice to vaccinate. Available online and as PDF in 23 languages including English, French, Spanish, Arabic, Chinese, and Indigenous languages).
- COVID-19 Vaccine: Multi-language information sheets (WCH): 2-page sheets on vaccine safety and efficacy, available in 11 languages including Tamil, Somali, Amharic, Bangla, and Punjabi.
- Vaccine resources for patients (WHO): Illustrated explanations of the steps in the vaccine development process. Available in 6 languages: English, French, Arabic, Chinese, Greek, and Spanish.
- Multilingual videos about vaccination for pregnant individuals (Born Ontario)
1-pagers and social media content (English)
- I got AstraZeneca for my first dose. Which vaccine is best for my second?” (University of Waterloo)
- Patient info sheet on the AstraZeneca and Johnson & Johnson vaccines (CEP, 2021)
- COVID-19 viral vector vaccines: FAQs (University of Waterloo)
- mRNA vaccine myths handout (University of Waterloo)
- mRNA vaccine myth poster (University of Waterloo)
- Vaccine development and approval in Canada (Government of Canada)
- The Facts about COVID-19 Vaccines (First Nations Health Authority)
- Understanding mRNA vaccines (Pfizer)
- COVID-19 vaccination flyer (City of Toronto)
Resources for Black communities
- Toronto Black Covid-19 Information portal: Includes data on the outsized negative impact of COVID-19 on Black communities and facts about the vaccines. A toolkit to support Black and racialized frontline workers is currently under development.
- Follow Toronto Black Covid Task Force (@TorontoTask) for news and resources.
Resources for Indigenous communities
- COVID-19 Vaccine FAQ (Métis Nation of Ontario, August 5, 2021).
- Maad’ookiing Mshkiki — Sharing Medicine information portal: Resources developed by The Centre for Wise Practices in Indigenous Health (CWP-IH) in partnership with Indigenous Primary Health Care Council (IPHCC), Anishnawbe Health Toronto (AHT) and The University Health Network, Indigenous Health (UHN) and Shkaabe Makwa (CAMH). Follow on twitter @SharingMedicine
- What you need to know about the COVID-19 vaccine for Canada (PHAC): 2-page information sheet on COVID-19 vaccines, including safety and efficacy, availability, prioritization, community immunity, cost and choice to vaccinate. Available online and as PDF in multiple Indigenous languages including Paskwāwinīmowin (Cree), Innu-aimun, Inuinnaqtun, Inuktitut (Nunavik), Mikmaq (Mi’kmaq), Ojibwe Eastern and Western and Oji-Cree.
Resources for people with intellectual and developmental disabilities (IDD)
- Health Care Access Research and Developmental Disabilities (H-CARDD) resources page
- Easy Read Information booklets give helpful information about the COVID vaccine in Canada (English and French)
- Vaccine Q&A videos
Resources for children and youth
- COVID-19 Vaccine Information Sheet: For Children (age 5-11) (Government of Ontario)
- Max Facts for Youth: Learn about the COVID-19 vaccine for 5 to 11 year olds (Ontario Association of Children’s Aid Societies/Canadian Medical Association)
- Vax Facts for Youth: Learn about the COVID-19 vaccine for 12 to 17 year olds (Ontario Association of Children’s Aid Societies/Unity Health Toronto)
- Kids Health First COVID-19 Vaccine site (Children’s COVID-19 Vaccine Advisory Table)
- COVID-19 vaccine for children and youth (Canadian Pediatric Society)
- FAQs: Covid-19 mRNA Vaccines for Children (University of Waterloo)
- Why now is the right time to vaccinate children (aged 5 to 11 years) against COVID-19
- The benefits of vaccinating children (ages 5 to 11) against COVID-19 (University of Waterloo)
- SickKids CARD System Learning Hub
- SickKids COVID-19 Vaccine Consult Service
- Children’s Health Coalition’s ParentHomework.ca
- What are the reasons to vaccinate my young child against COVID-19
- Timing of COVID-19 Vaccines
- What you need to know: Fever (Children’s Hospital of Eastern Ontario)
Resources for Pregnant and Breastfeeding Individuals
Top resources
Pfizer-BioNTech COVID-19 vaccine
- Pfizer-BioNTech COVID-19 Vaccine Info Sheet (MOH, December 13, 2020)
- Pfizer-BioNTech COVID-19 vaccine: What you should know (Health Canada, December 16, 2020)
- Pfizer-BioNTech COVID-19 vaccine: Patient medication information handout (English and French)
- Safety and Efficacy of the BNT162b2 mRNA COVID-19 vaccine (NEJM, Dec 10, 2020)
- Product monograph, including patient medication information: Pfizer-BioNTech COVID-19 vaccine (March 3, 2021)
- Details for: Pfizer-BioNTech COVID-19 Vaccine (Health Canada, Nov 13, 2020)
Moderna COVID-19 vaccine
- Product monograph, including patient medication information: Moderna COVID-19 Vaccine (Moderna, July 14, 2022)
- Moderna COVID-19 vaccine: What you should know (Health Canada, December 23, 2020)
- Moderna COVID-19 vaccine: Patient medication information handout (English)
- Moderna COVID-19 vaccine: Authorization information (Health Canada December 23, 2020)
- Moderna COVID-19 vaccine: Interim order authorization – terms and conditions (Health Canada, December 23, 2020)
- Product details: Moderna COVID-19 Vaccine (mRNA-1273 SARS-CoV-2) (Health Canada, December 23, 2020)
- Consumer information: Details for Moderna COVID-19 vaccine / vaccin de Moderna contre la COVID-19 (Health Canada, December 23, 2020)
- Efficacy and Safety of the mRNA-1273 SARS-CoV-2 Vaccine (NEJM, December 30, 2020)
Oxford-AstraZeneca COVID-19 vaccine
- AstraZeneca COVID-19 vaccine: What you should know (Health Canada, February 26, 2021)
- AstraZeneca COVID-19 vaccine: Patient medication information handout (English)
- Product monograph, including patient medication information: AstraZeneca COVID-19 vaccine (April 14, 2021)
- Details for: AstraZeneca COVID-19 Vaccine (Health Canada, February 26, 2021)
- Safety and efficacy of the ChAdOx1 nCoV-19 vaccine (AZD1222) against SARS-CoV-2: an interim analysis of four randomised controlled trials in Brazil, South Africa, and the UK (Lancet, January 9, 2021)
Janssen (Johnson & Johnson) COVID-19 vaccine
- Janssen COVID-19 vaccine: What you should know (Health Canada, March 5, 2021)
- Janssen COVID-19 vaccine: Patient medication information handout (English)
- Product monograph, including patient medication information: Janssen COVID-19 vaccine (March 5, 2021)
- Details for: Janssen COVID-19 Vaccine (Health Canada, March 5, 2021)
General vaccine information
- COVID-19 vaccination in Canada: an educational series for primary care professionals (DFCM/OCFP, 2021)
- COVID-19 vaccine safety in Canada (Health Canada)
- About Vaccines (MOH, January 6, 2020)
- Vaccine development and approval in Canada Infographic (Government of Canada, 2020)
- Vaccine Approval Process and Safety (MOH, December 30, 2020)
- What you need to know about the COVID-19 vaccine for Canada (PHAC, 2020)
- Recommendations on the use of COVID-19 vaccine(s) (NACI, March 1, 2021)
- Health Canada: Guidance on the prioritization of initial doses of COVID-19 vaccine(s)
- Vaccine Availability and Rollout (MOH, January 6, 2021)
- COVID-19 Vaccine Administration (MOH, October 20, 2021)
- MyVaccines.ca
- COVID-19 mRNA vaccines (Health Canada, December 11, 2020)
- Getting a COVID-19 vaccine in Ontario (Government of Ontario, Jan 2021)
- Vaccines and treatments for COVID-19: Vaccine rollout (Health Canada)
- SOGC Statement on COVID-19 Vaccination in Pregnancy (March 12, 2021)
These supporting materials and resources are hosted by external organizations. The accuracy and accessibility of their links are not guaranteed. CEP will make every effort to keep these links up to date.
Acknowledgement and legal
The COVID-19: Vaccines Resource was developed by the Centre for Effective Practice (CEP) with support from Ontario College of Family Physicians (OCFP), Nurse Practitioners’ Association of Ontario (NPAO), Association of Family Health Teams of Ontario (AFHTO), Ontario Medical Association (OMA), Registered Nurses’ Association of Ontario (RNAO), Ontario College of Pharmacists, Section of General and Family Physicians of Ontario (OMA, SGFP), the Department of Family Medicine at McMaster University and the School of Pharmacy at the University of Waterloo, funded by the Ministry of Health and Long-Term Care.
Clinical expertise and input provided by:
• Alykhan Abdulla MD, CCFP, FCFP, DIPSPORTMED CTH CCPE MCPL ICD.d
• Cora Constantinescu BSc, MD, FRCPC
• Kelly Grindrod BScPharm, PharmD, MSc
• Nancy Lum-Wilson R.Ph., B.Sc.Phm., MBA
• Noah Ivers MD, PhD, CCFP
Thank you to everyone who supported the development of this resource.
Conflict of interest
• Clinical Leads receive compensation for their role
• Clinical Working Group receive an honorarium for their participation
• Focus group and usability participants receive a small token of appreciation (e.g. gift certificate)
The COVID-19: Vaccines resource is a product of the Centre for Effective Practice. Permission to use, copy, and distribute this material for all non-commercial and research purposes is granted, provided the above disclaimer, this paragraph and the following paragraphs, and appropriate citations appear in all copies, modifications, and distributions. Use of the COVID-19: Vaccines resource for commercial purposes or any modifications of the Tool are subject to charge and use must be negotiated with the Centre for Effective Practice (Email: info@cep.health).
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