Vaccine FAQ
Is it safe to receive a different mRNA vaccine (Pfizer-BioNTech and Moderna) for my second dose?
Yes, it is safe to receive a different mRNA vaccine for your second dose from the first dose you received (i.e. first dose = Pfizer-BioNTech, second dose = Moderna OR first dose = Moderna, second dose = Pfizer-BioNTech). Both the Pfizer-BioNTech and Moderna mRNA vaccines are interchangeable, equally effective and safe for everyone over 18 years of age. Read more in this document from the Ontario Ministry of Health.
Only the Pfizer-BioNTech mRNA vaccine will be administered to youth age 12 to 17. This is because Pfizer-BioNTech is the only vaccine currently approved in Canada for those under 18.
Both vaccines are safe for people with most health conditions — including those who are immunocompromised, pregnant or breastfeeding and those who have diabetes. If you have specific health concerns, please speak with your doctor before your vaccine appointment.
If you are concerned about allergies to vaccine ingredients, please review the vaccine ingredients here:
Which vaccines have been approved for use in Canada?
Four vaccines have been approved by Health Canada:
- Pfizer-BioNTech – approved on Dec. 9, 2020
- Moderna – approved on Dec. 23, 2020
- AstraZeneca – approved on Feb. 26, 2020
- Janssen – approved on Mar. 5, 2020
More information on the approval process can be found on the Health Canada website.
Are the COVID-19 vaccines safe?
Yes. The vaccines have been tested in extensive clinical trials and proven safe for individuals who do not meet certain exclusion criteria.
More information on vaccine safety can be found on the Health Canada website.
The vaccines were developed in less than one year. How did that happen?
The Health Canada approved COVID-19 vaccines have gone through the same rigorous process as all approved drugs. This happened so quickly because it was a top priority, and there was dramatically increased funding and collaboration.
Are the vaccines effective?
The vaccine is not 100 per cent effective. There’s still a small chance that you could get COVID-19 after getting the vaccine. Continue to follow all advice from public health and your care team.
How do the vaccines work?
Both the Pfizer-BioNTech and Moderna vaccines are mRNA vaccines, which work by teaching our cells to make a protein that triggers an immune response to COVID-19 without using the live virus that causes COVID-19. This immune response results in the production of antibodies, which help us fight infection if the real virus enters our body in the future.
The AstraZeneca and the Janssen vaccines are viral vector-based vaccines – they use a harmless virus as a delivery system. The virus is not COVID-19. When a person is given the vaccine, the vector virus contained within the vaccine produces the SARS-CoV-2 spike protein. This protein is found on the surface of the virus that causes COVID-19. This protein will not make you sick. It does its job and goes away. Through this process, the body is able to build a strong immune response against the spike protein without exposing you to the virus that causes COVID-19.
More information can be found on the Health Canada website.
How is the vaccine given?
The Pfizer-BioNTech, Moderna and AstraZeneca vaccines are given by injection into the muscle of the arm.
More information can be found on the Health Canada website.
What are the potential side effects of the vaccine?
Some people who get the vaccine have mild side effects. These can include pain, redness or swelling where the needle went in, a sore muscle, headache or fever. These are normal and are signs that the vaccine is working.
Please speak with your health professional about any serious allergies or other health conditions you may have before you receive any vaccine.
What are the ingredients in the vaccines?
A list of ingredients in the vaccines can be found on their Health Canada product pages:
Can I get COVID-19 from the approved vaccines?
You can’t get COVID-19 from the COVID-19 vaccines.
The Pfizer-BioNTech and Moderna vaccines are mRNA vaccines that don’t contain the live virus and therefore cannot cause the illness.
The AstraZeneca and the Janssen vaccines are viral vector-based vaccines – they use a harmless virus as a delivery system. The virus is not COVID-19. When a person is given the vaccine, the vector virus contained within the vaccine produces the SARS-CoV-2 spike protein. This protein is found on the surface of the virus that causes COVID-19. This protein will not make you sick. It does its job and goes away. Through this process, the body is able to build a strong immune response against the spike protein without exposing you to the virus that causes COVID-19.
Is it necessary for young healthy adults to get the vaccine?
We will only beat COVID-19 when the majority of people get vaccinated. If all eligible young adults get the vaccine, we can achieve herd immunity and stop the spread of the virus.
Once I have been vaccinated, do I need to continue to follow public health measures?
Yes, you still need to wear a mask, wash your hands often and keep a safe distance once you have been vaccinated. Although both COVID-19 vaccinations provide protection against symptomatic infection, we don’t yet know whether they prevent the recipient from spreading the virus to others.
Can I get the COVID-19 vaccine if I am pregnant, breastfeeding or planning to get pregnant?
If you are pregnant, breastfeeding, or planning to get pregnant, you can choose to get the COVID-19 vaccine. Speak with your doctor about your options.
Can I get the vaccine if I am immunocompromised?
People with most health conditions, including those who are immunocompromised, can get the COVID-19 vaccine. Speak with your doctor about your options.
Last updated July 30, 2021