About COVID-19 Vaccines


COVID-19 vaccines are safe and effective, and an important tool in our response to the pandemic. Health Canada has approved three vaccines for use in Canada. Pfizer-BioNTech was approved on December 9, 2020, Moderna was approved on December 23, 2020, AstraZeneca was approved on February 26, 2021 and Janssen was approved on March 5, 2021.


For information about these COVID-19 vaccines, see the following resources:

What you should know about the COVID-19 vaccines (ontario.ca)

Public Health Ontario - What You Need to Know About COVID-19 Vaccine

About COVID-19 Vaccines (gov.on.ca)

COVID-19 Pfizer and Moderna About Vaccines (gov.on.ca)

Getting a COVID-19 vaccine in Ontario

Ministry of Health - COVID-19 Vaccine Information Sheet For Youth (ages 12-17)

Ministry of Health - COVID-19 Vaccine Information Sheet

Ontario Pauses Administration of AstraZeneca Vaccine | Ontario NewsroomOntario Updating AstraZeneca Second Dose Guidance | Ontario Newsroom



All vaccines work by presenting our body with something that looks like the infection so that our immune system can learn how to produce natural protection. This natural protection then helps to prevent future illness if you come into contact with the COVID-19 virus in the future. You cannot get COVID-19 from the vaccine.

mRNA vaccines (Pfizer-BioNTech and Moderna COVID-19 vaccines) provide our cells with instructions on how to produce a copy of a protein that is found on the surface of the COVID-19 virus. Our bodies recognize this protein which is what starts our immune response. mRNA vaccines are not live vaccines and cannot cause infection in the host. mRNA vaccines also cannot alter a person’s DNA.


Viral vector vaccines (AstraZeneca/COVISHIELD COVID-19 vaccines) Use a genetically modified virus that cannot cause disease, to deliver genetic instructions (DNA) to our cells to produce coronavirus protein that initiates an immune response in the body. Viral vector vaccines cannot cause infection in the host (i.e. they are non-replicating) and cannot alter a person’s DNA.


COVID-19 Vaccines: Viral Vector-based Vaccines (publichealthontario.ca)



About COVID-19 Vaccines (gov.on.ca)

What You Need to Know About COVID-19 Vaccine (publichealthontario.ca)

All COVID-19 vaccines authorized for use in Canada are effective at protecting against symptomatic, lab-confirmed disease. In large studies where people were given both doses of the vaccine, all of the vaccines worked very well to prevent people from becoming sick with symptomatic, lab-confirmed COVID-19. It is important that you receive two doses of these vaccines as long-term protection against COVID-19 is not achieved until after the second dose of vaccine is received.

Evidence indicates that vaccines are very effective at preventing severe illness, hospitalization and death from COVID-19, including against alpha and delta variants of concern. If you are vaccinated and get infected – “a breakthrough case” – your symptoms should be milder and have less severe health impacts for you personally and for the health system.


COVID-19: Effectiveness and benefits of vaccination - Canada.ca


COVID-19 vaccines are safe. Health Canada only approves a vaccine if it supported by very robust scientific data and evidence.

Learn more about the safety of COVID-19 vaccines, how they work and possible side effects, visit Ontario’s COVID-19 vaccine safety webpage.

Other Resources:

At a Glance: Vaccine Regulatory Process in Canada (publichealthontario.ca)

COVID-19 Vaccine Approval Process and Safety (gov.on.ca)

COVID-19: How vaccines are developed (video) - Canada.ca

Vaccine development and approval in Canada - Canada.ca

COVID-19 vaccines, like all vaccines, may cause side effects, although not everyone experiences them and those who do experience them mostly report minor side effects. The most commonly reported side effects after receiving a COVID-19 vaccine are localized reactions including pain, redness or swelling at the injection site, tiredness, headache, muscle pain, joint pain, chills, and mild fever.

Ongoing studies on these COVID-19 vaccines indicate serious side effects found to date are extremely rare. People who have received the vaccine in these studies continue to be monitored for any longer-term side effects.

Clinic staff are prepared to manage a severe allergic reaction should it occur. When receiving your second dose of COVID-19 vaccine, be sure to tell the health care provider administering the second dose if you had any side effects after the first dose.

Vaccine Side Effects

Vaccine Side Effects - Rash

COVID-19 Vaccine Information Sheet V9.0 - English (gov.on.ca)

When they are eligible, vaccines should be offered to individuals without contraindications to the vaccine.

If you have any symptoms that could be due to COVID-19, you should not receive the vaccine at this time. You should also wait 14 days after receiving any other vaccine before receiving the COVID-19 vaccine.

There are special considerations for specific populations including pregnancy, people with autoimmune conditions, people who are immunocompromised and people with severe allergies to vaccine ingredients. If you have questions about if the COVID-19 vaccine is right for you, speak to your health care provider.

Other Resources

SOGC Statement - COVID-19 Vaccination in Pregnancy

COVID-19 Vaccine and Pregnancy Poster

COVID-19 Vaccine Promotion Poster for Healthcare Workers

COVID-19 Vaccination: Special Populations - Vaccination in Pregnancy & Breastfeeding Patient Decision-Making Tool

Youth and COVID-19 Vaccines (publichealthgreybruce.on.ca)

The vaccine is an additional way to protect yourself against COVID-19. After either dose of the COVID-19 vaccine you should continue to follow COVID-19 measures, such as wearing a mask, practising physical distancing and washing your hands. Continue to monitor for symptoms of COVID-19 and get tested if symptoms present.

Provincial Vaccine Information Line: 1-888-999-6488; Hours of Operation - 8AM-8PM, Monday-Sunday (Provincial Telephone Info Line)

Anyone looking for more information on the COVID-19 vaccine, as it relates to his or her personal health situation is encouraged to discuss this with his or her doctor. Anyone who fits into one of the following special patient groups should speak with their doctor ahead of booking their appointment to ensure the vaccine is right for them:

  • Those who are pregnant
  • Those who have autoimmune conditions or are immunocompromised (due to disease or treatment)
  • Those who have had a severe allergic reaction or anaphylaxis to a previous dose of a COVID-19 mRNA vaccine or to any of its components.
  • If you have any questions about your health condition and are concerned about getting the vaccine, you must talk to your primary care provider about this directly. Public Health will not give individual clinical guidance on this decision.  You must talk to you provider about these concerns.

You can review vaccination recommendations for special populations for more information. COVID-19 Vaccination Recommendations for Special Populations (gov.on.ca)

Visit the About COVID-19 Vaccines (publichealthgreybruce.on.ca) webpage to learn more about COVID-19 vaccines.


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