Reported side effects following COVID-19 vaccination in Canada

We update this page every Friday at 12:00 PM Eastern Time. A detailed technical report is available.

Summary of this week's report updated December 10, 2021

• A total of 61,495,494 vaccine doses have been administered in Canada as of December 3, 2021. Adverse events (side effects) have been reported by 28,825 people. That’s about 5 people out of every 10,000 people vaccinated who have reported 1 or more adverse events .
  • Of the 28,825 individual reports, 22,244 were considered non-serious ( 0.036% of all doses administered ) and 6,581 were considered serious ( 0.011% of all doses administered ).
  • Most adverse events are mild and include soreness at the site of injection or a slight fever.
  • Serious adverse events are rare , but do occur. They include anaphylaxis (a severe allergic reaction), which has been reported 683 times for all COVID-19 vaccines across Canada. That’s why you need to wait for a period of time after you receive a vaccination so that you can receive treatment in case of an allergic reaction.
• All serious events undergo medical review to see if there are any safety issues needing further action. These processes include meeting regularly to review the data with provincial and territorial partners, the regulator, research networks and medical advisors to ensure there are no safety issues that require action. Any unexpected safety concerns are detected quickly and acted upon immediately.
• The Public Health Agency of Canada (PHAC) and Health Canada continue to closely monitor Canadian and international reports of:
• Thrombosis with thrombocytopenia syndrome following vaccination with AstraZeneca Vaxzevria/COVISHIELD COVID-19 vaccine. Health Canada has updated the AstraZeneca Vaxzevria COVID-19 vaccine product monograph (PDF) and the COVISHIELD COVID-19 vaccine product monograph (PDF) to include information about these very rare events of blood clots associated with low levels of platelets following immunization. For more information, please refer to the AstraZeneca Vaxzevria/COVISHIELD COVID-19 vaccine public advisory .
• Guillain-Barré Syndrome (GBS) in Canada following AstraZeneca Vaxzevria/COVISHIELD COVID-19 vaccination. Data in Canada indicate a higher number of reports than would normally be expected in the general population. Health Canada has updated the AstraZeneca Vaxzevria COVID-19 vaccine product monograph (PDF) and the COVISHIELD COVID-19 vaccine product monograph (PDF) to include information on GBS. For more information, please refer to the AstraZeneca Vaxzevria/COVISHIELD COVID-19 vaccination product description.
• Myocarditis (inflammation of the heart muscle) and pericarditis (inflammation of the lining around the heart) following vaccination with COVID-19 mRNA vaccines. Data in Canada indicate a higher number of reports in younger people (i.e. less than 40 years of age) than would normally be expected in this age group in the general population. Health Canada updated the Moderna Spikevax COVID-19 vaccine product monograph (PDF) and the Pfizer-BioTech Comirnaty COVID-19 vaccines product monograph (PDF) to include information around these risks. For more information, please refer to the Moderna Spikevax and Pfizer-BioNTech Comirnaty COVID-19 vaccines public advisory .
• Capillary leak syndrome following vaccination with the AstraZeneca Vaxzevria/COVISHIELD COVID-19 vaccine. Health Canada has updated the AstraZeneca Vaxzevria COVID-19 vaccine product monograph (PDF) and the COVISHIELD COVID-19 vaccine product monograph (PDF) to include information on capillary leak syndrome, including a contraindication for patients who have previously experienced this syndrome. For more information, please refer to the AstraZeneca Vaxzevria/COVISHIELD COVID-19 vaccine public advisory.
• Facial paralysis/Bell’s Palsy following COVID-19 vaccination. Health Canada has updated Moderna Spikevax COVID-19 vaccine product monograph (PDF) and the Pfizer-BioNTech Comirnaty COVID-19 vaccine product monograph (PDF) to include information on facial paralysis/Bell’s Palsy.
• Immune thrombocytopenia (ITP) and venous thromboembolism (VTE) following vaccination with the Janssen COVID-19 vaccine. Health Canada has updated the Janssen COVID-19 vaccine product monograph (PDF) to include information on ITP and VTE. For more information, please refer to the Janssen and AstraZeneca Vaxzevria COVID-19 vaccines public advisory.
• Thrombocytopenia including ITP following vaccination with AstraZeneca Vaxzevria COVID-19 vaccine. Health Canada has updated the AstraZeneca Vaxzevria COVID-19 vaccine product monograph (PDF) to include information on thrombocytopenia including ITP. For more information, please refer to the AstraZeneca Vaxzevria COVID-19 vaccine public advisory.
• The benefits of vaccines authorized in Canada continue to outweigh the risks.

Additional information

Canada’s independent drug authorization process is known around the world for its high standards and rigorous review process. Decisions are based on scientific and medical evidence. Vaccines authorized for use in Canada are safe, effective and of high quality.

The work to make sure a vaccine is safe starts before the regulatory process even begins. Exploratory, preclinical studies, and clinical trials are designed to assess the vaccine’s safety. Evidence from these activities is submitted to Health Canada for regulatory review. Health Canada’s scientific and medical reviewers then conduct a thorough and independent review of all vaccine data. Only then is a vaccine authorized for use in Canada. Learn more about how vaccines are approved in Canada.

Health Canada authorized booster doses of Pfizer-BioNTech Comirnaty on November 9, 2021 and Moderna Spikevax on November 12, 2021 . Booster doses are administered intramuscularly to adults at least 6 months after they complete their primary series. On November 19, 2021, the authorization of Pfizer-BioNTech Comirnaty was extended to children 5 to 11 years of age (10 mcg dose). Health Canada authorized the AstraZeneca Vaxzevria COVID-19 vaccine on November 19, 2021 and the Janssen COVID-19 vaccine on November 23, 2021 under the Food and Drug Regulations . Get more information about the authorized vaccines:

• Pfizer-BioNTech Comirnaty COVID-19 vaccine
  • Information on Pfizer-BioNTech Comirnaty boosters
  • Information on the Pfizer-BioNTech Comirnaty vaccine for children 5 to 11 years of age
• Moderna Spikevax COVID-19 vaccine
  • Information on Moderna Spikevax boosters
• AstraZeneca Vaxzevria COVID-19 vaccine
  • Information on AstraZeneca Vaxzevria authorization
• Janssen (Johnson & Johnson) COVID-19 vaccine
  • Information on Janssen authorization

After a vaccine is authorized, Health Canada, PHAC, manufacturers, and public health authorities continue to review and monitor the adverse event (side effect) data as vaccines are administered to Canadians.

Drug manufacturers (or sponsors) must also monitor and act on safety issues. They develop and update detailed product monographs, which explain how to safely and effectively use a drug or vaccine. The most recent product monographs for approved COVID-19 vaccines are in the COVID-19 vaccines and treatments portal . Health Canada regularly updates a Post-Authorization Activity Table (PAAT) for each COVID-19 vaccine and treatment. The PAAT summarizes activities since authorization. This includes product monograph updates for each vaccine authorized for use in Canada:

• PAAT for Pfizer-BioNTech Comirnaty COVID-19 vaccine
• PAAT for Moderna Spikevax COVID-19 vaccine
• PAAT for COVISHIELD
• PAAT for AstraZeneca Vaxzevria COVID-19 vaccine
• PAAT for Janssen (Johnson & Johnson) COVID-19 vaccine

Some people have reported adverse events (side effects) after being immunized with a COVID-19 vaccine in Canada. These adverse events aren’t necessarily related to the vaccine. For example, they may be:

• anxiety about immunization
• an allergic reaction to another substance
• related to a pre-existing condition
• coincidental

If you experience an adverse event following immunization with a COVID-19 vaccine in Canada, please contact your healthcare provider. Learn more about reporting adverse events .