COVID-19 Vaccine Fact Sheet

Health Canada has authorized the use of COVID-19 vaccines produced by Pfizer-BioNTech and Moderna. Both vaccines have been tested in large clinical trials to ensure they meet safety standards, and both have been licensed and approved by Health Canada.


COVID-19 is a viral infection. The long-term effects of COVID-19 are not fully known. Some people are at greater risk of getting COVID-19 because of their work or living conditions. Some people may have a mild illness or no symptoms at all. Others may get very sick, including seniors or people with pre-existing health conditions. Very rarely, some children can get a serious inflammatory condition.

How these Vaccines Work

The vaccine tells the cells in our body to make a protein that is found specifically on the virus that causes COVID-19. These “spike proteins,” although harmless to us, will trigger our body to start making antibodies. Our new antibodies will protect us from being sick if we are exposed to the virus. The vaccine does not contain the virus and so it cannot give us COVID-19.

Both vaccines have been tested in large clinical trials to ensure they meet safety standards, and both have been licensed and approved by Health Canada.

Vaccination Process

Both vaccines require two doses. The doses are given at least 21-28 days apart for those eligible to receive it. Speak to your health care provider or your local Public Health Unit to see if you are eligible.

Vaccine Benefits

Two doses of the vaccine are required for better protection. After completing the two-doses, it may take another one to two weeks to achieve maximum protection against COVID-19. At this time, there is no information on the long-term protection of this vaccine. In trials, the vaccine was 95% effective.

There is a small chance that you may still get COVID-19 after being vaccinated. It is important to continue with public health measures such as physical distancing, wearing a mask, and staying home if you are sick. Health care and other staff must still wear personal protective equipment (PPE) even after they have been vaccinated.

Side Effects and Risks

Some people may experience side effects from the vaccine, but they will likely be moderate and resolve after a few days. Some of the symptoms are part of the body’s response to developing immunity.

In rare cases, serious allergic reactions (anaphylaxis) can occur. Allergic reactions can be treated and are usually temporary. Seek medical attention if you have trouble breathing, have hives or swelling of the face and throat. Vaccine side effects will continue to be monitored as people receive the vaccine.

If you get a reaction to the vaccine, contact your health care provider who will report the side effect directly to public health. Public health will keep track of the reported side effects to make sure the vaccine continues to be safe.


  • Delay vaccination if you feel unwell, or have received another vaccine in the past 14 days.
  • Speak to your health care practitioner if you are trying to get pregnant before getting the vaccine.
  • If you are on blood thinner medication, they will use a different needle and you will need to apply pressure after getting the vaccine to reduce bruising.

Do not get this vaccine if you:

  • have known allergies to any vaccine ingredients, including polyethylene glycol; or
  • have had a severe reaction to your first dose of this vaccine.

Talk to your health care provider first if you:

  • are under 16 years of age;
  • are pregnant or breastfeeding or thinking of becoming pregnant; or
  • have a weakened immune system due to illness or treatment, or a bleeding disorder.

You can read more about Ontario’s vaccine distribution implementation plan on the website. For more information, talk to your health care provider, or visit Ontario's Public Health COVID-19 information page.

This article contains information from Toronto Public Health.

Last updated: January 8, 2021 4006453