COVID-19: Vaccines and Boosters

• Booster recommended: No
• Eligible number of doses (including primary series): 3 (for Pfizer), and 2 (for Moderna) 
• NACI Recommendations for staying up to date: A completed primary series.

_{Note: The number of eligible doses may differ between patients, and if vaccines other than Pfizer or Moderna are used (e.g., Novavax, Janssen).} 

• Booster recommended: Yes
  
• Which vaccine: Pfizer 10mcg original
• Interval (previous vaccine or infection): 6 mos or 3mos*
• Eligible number of doses (including primary series): 3, or 4 for immunocompromised, 5 years and older
  
• NACI Recommendations for staying up to date: A completed primary series and receipt of a booster dose (monovalent or bivalent) on or after September 1, 2022. For high-risk populations, this also means completion of the primary series and receipt of a booster dose if it has been 6 months since their last dose or a COVID-19 infection. 

_{*a shorter interval of at least 3 months may be warranted in the context of heightened epidemiologic risk, as well as operational considerations for the efficient deployment of the program.}

_{Note: The number of eligible doses may differ between patients, and if vaccines other than Pfizer or Moderna are used (e.g., Novavax, Janssen).} 

• Booster recommended: Yes
  
• Which vaccine: Pfizer 30mcg bivalent 
• Interval (previous vaccine or infection): 6 mos or 3mos*
• Eligible number of doses (including primary series): 5
• NACI Recommendations for staying up to date: A completed primary series and receipt of a booster dose (monovalent or bivalent) on or after September 1, 2022. For high-risk populations, this also means completion of the primary series and receipt of a booster dose if it has been 6 months since their last dose or a COVID-19 infection.

_{*a shorter interval of at least 3 months may be warranted in the context of heightened epidemiologic risk, as well as operational considerations for the efficient deployment of the program.}

_{Note: The number of eligible doses may differ between patients, and if vaccines other than Pfizer or Moderna are used (e.g., Novavax, Janssen).} 

• Booster recommended: Yes
  
• Which vaccine: Pfizer 30mcg bivalent, Moderna 50mcg bivalent 
  
• Interval (previous vaccine or infection): 6 mos or 3mos*
• Eligible number of doses (including primary series): 5
• NACI Recommendations for staying up to date: A completed primary series and receipt of a booster dose (monovalent or bivalent) on or after September 1, 2022. For high-risk populations, this also means completion of the primary series and receipt of a booster dose if it has been 6 months since their last dose or a COVID-19 infection.

_{*a shorter interval of at least 3 months may be warranted in the context of heightened epidemiologic risk, as well as operational considerations for the efficient deployment of the program.}

_{Note: The number of eligible doses may differ between patients, and if vaccines other than Pfizer or Moderna are used (e.g., Novavax, Janssen).} 

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).

NACI has also recommended an interval of 6 months or more between a primary series for children ages 5-11 and a booster dose of pediatric Pfizer vaccine in order to increase immune response and promote longer lasting immunity (NACI, August 19, 2022).

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. Based on the clinical trials, efficacy in children ages 6 months – 4 years old was estimated to be consistent with vaccine efficacy in adults.

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)

It’s recommended that children aged five years and above receive the Pfizer vaccine approved for the five to 11 age group. (Sickkids, August 11, 2022).

Children who received a Moderna dose (25 mcg) and turn five years old prior to completing their primary series are recommended to receive Moderna (25 mcg) to complete their primary series. (MOH, September 7, 2022).

Children aged 4 who will turn 5 years of age between their Pfizer doses in the vaccination series should receive their age-appropriate dose at the time of the vaccination. The interval between doses is determined by the child’s age at the start of the vaccination series. Doses are 10 mcg for children ages 5 to 11, and 3 mcg for children 6 months to less than 5 years of age. (Health Canada, September 9, 2022).

It is recommended that children be vaccinated as soon as possible since they are usually more at risk of becoming increasingly ill if infected with COVID-19 (MOH, Aug 2022).  

 For children 6 months to 5 years of age who are moderately to severely immunocompromised, a third dose of the COVID-19 vaccine may be offered. Children 5 years of age and older who are moderately to severely immunocompromised should receive 3 doses of the vaccine. It is recommended to wait 4 to 8 weeks before receiving the next dose (Health Canada, July 14th, 2022). 

Our immune systems weaken with age, allowing children the ability to receive smaller doses than adults while still developing the same protection from COVID-19 (MOH, Aug 2022).  

Dose volumes will vary depending on the age and product: 

• Moderna COVID-19 vaccine: 
  • Children 6 months to 5 years: 25mcg 
  • Children 6 months to 11 years: 50 mcg 
  • Youth 12 years of age and older: 100mcg 
• Pfizer COVID-19 vaccine: 
  • Children 5 to 11 years: 10 mcg 
  • Youth 12 years and older: 30 mcg 
  • Children 6 months to 5 years: 3 mcg

Both the Moderna and Pfizer COVID-19 vaccines are approved for individuals 6 months and older.

The Moderna COVID-19 vaccine has been authorized for use as a primary series in children 6 to 11 years of age with a dose of 50 mcg, and for children 6 month of aged to 5 years of age, a 25 mcg dose has been authorized. Booster doses of Moderna (50 mcg) are authorized for persons 18 years of age and older (NACI, August 19, 2022).

The Pfizer COVID-19 vaccine has been approved for children 6 months to less than 5 years of age as a 3-dose primary series of 3 mcg. The initial 2 doses are administered 21 days apart followed by a third dose administered at least 8 weeks after the second dose. For children 5 to 11, a 10 mcg dose is approved, and 30 mcg for ages 12 and older. A single booster dose of the Pfizer COVID-19 vaccine may be administered in individuals 5 years of age and older at least 6 months after completing their primary vaccine series (10 mcg each for ages 5 to 11 or 30 mcg each for ages 12 and older) (Health Canada, Sept 9, 2022).

Clinical trials regarding the Moderna COVID-19 vaccine for children 6 months to 5 years of age demonstrated that after 103 days of receiving the first dose, no safety signals were identified meaning no serious side-effects were developed as a result of the COVID-19 vaccine. The benefits of the vaccine far outweigh any risks or side effects. It is possible that COVID-19 infection may cause longer lasting symptoms and health problems therefore vaccination as soon as possible is important (MOH,  Aug 2022).

NACI recommends pregnant and breastfeeding individuals should be offered a complete vaccine series with an mRNA COVID-19 vaccine. NACI further recommends a booster at any stage of pregnancy (regardless of how many boosters were previously received). The vaccines can be administered before, after, or on the same day as other vaccines.  

 As with the recommendations offered for other populations, boosters are recommended at a 6-month interval following a previous dose and/or infection (or 3 months for those at an increased risk). Breastfeeding can also continue after vaccination, and it will not have an adverse impact on infants or children (Government of Canada, March 23, 2023).

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.

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.

Children 6 months and older are eligible for the COVID-19 vaccine despite whether or not they are breastfed. Breastfeeding individuals pass along antibodies through their breast milk and these antibodies do not interfere with immunity acquired from the vaccine; this allows for added protection. Vaccination does not need to be delayed or timed differently for children 6 months and older who are being breastfed (MOH, Aug 2022).  

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:

• The Vatican and the Canadian Conference of Catholic Bishops
• Muslim American Society
• Canadian Muslim COVID-19 Task Force
• World Jewish Congress and World Council of Churches
• Orthodox Union and Rabbinical Council of America

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

• Product monograph, including patient medication information: Pfizer-BioNTech COVID-19 vaccine, February 8, 2021
• Moderna Covid-19 Vaccine Product Monograph, February 19, 2021
• AstraZeneca COVID-19 Vaccine Product Monograph, March 24, 2021

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)

No. Booster doses will not affect the results of viral tests for SAR-CoV-2 (CDC, September 28, 2022). The current authorized and recommended mRNA vaccines do not contain the live virus, and therefore, will not result in a positive viral test for current infection (CDC, February 16, 2023).

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.

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.

Ontarians ages 12 and older are eligible for a bivalent vaccine booster 6 months after their previous dose. NACI strongly recommends that bivalent COVID-19 vaccines be the preferred booster given to anyone in the approved age group. Ontarians aged 12 and older are eligible for the Pfizer bivalent vaccine, and Ontarians ages 18 and older are eligible for both the Moderna BA.1 bivalent vaccine and Moderna BA.4/5 bivalent vaccine (NACI, November 3, 2022)

High risk individuals are encouraged to get a bivalent booster 3 months after their previous dose. This includes those who are (Ontario, October 19, 2022)

• Aged 65 and older
• First Nations, Inuit and Métis individual or a non-Indigenous household member, aged 18 and older
• Resident of a long-term care home, retirement home or Elder Care Lodge
• An individual living in other congregate settings that provide assisted living and health services
• Individuals aged 12 and older with an underlying medical condition that places them at high risk of severe COVID-19
• Pregnant, aged 18 and older
• Health care workers, aged 18 and older

• 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.

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.

• 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)

• 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.

References

• Product monograph, including patient medication information: Pfizer-BioNTech COVID-19 vaccine (February 8, 2021)
• Product monograph, including patient medication information: Moderna COVID-19 Vaccine (Moderna, December 2020)

• 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.

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.

See COVID-19: Clinical Guidance for Primary Care Providers: Long-term symptoms / Post-acute sequelae of COVID-19 (PASC)

• 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)

• No. They do not contain mercury, formaldehyde, aluminum, or fetal cells.

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).

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.

Including Omicron in an updated booster vaccine may increase protection against variants such as Omicron BA.4 and BA.5. The BA.1- targeted, bivalent mRNA vaccines may also result in an immune response which provides additional protection against future variants; however, this is not certain at the moment (NACI, September 1, 2022). For context, the bivalent vaccine targeting Omicron can be considered like the flu vaccine targeting a different strain each year. 

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. Data collected from vaccines administered at an extended interval indicate 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 (3-5 months) to access an Omicron-targeted dose in the fall in order to provide optimal protection (Clin Infect Dis. April 19, 2022; Alberta Health Services, July 20, 2022). The 3-month interval is likely for those who are immunosuppressed (OCFP, July 21, 2022). Research on this topic is ongoing.

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).

In the Moderna Bivalent clinical trial, no participants were administered additional vaccines at the same time. Thus, there is limited information on the safety and immunogenicity of COVID-19 vaccines being administered simultaneously as other vaccines. To date, there are not any specific safety concerns. There is also no data to date on using bivalent Omicron-containing mRNA COVID-19 vaccines as a primary series, first booster dose or in a mixed series with vaccines other than Moderna Spikevax original (NACI, September 1, 2022). 

For more information, please review the NACI recommendations. 

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).