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 September 17, 2021

• A total of 54,129,701 vaccine doses have been administered in Canada as of September 10, 2021. Adverse events (side effects) have been reported by 15,298 people. That’s about 3 people out of every 10,000 people vaccinated who have reported 1 or more adverse events .
  • Of the 15,298 individual reports, 11,126 were considered non-serious ( 0.021% of all doses administered ) and 4,172 were considered serious ( 0.008% 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 172 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 product monograph to include information about these very rare events of blood clots associated with low levels of platelets following immunization.
• 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/COVISHIELD product monograph to include information on GBS.
• 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 product monographs for both Moderna Spikevax and Pfizer-BioTech COVID-19 vaccines to include information around these risks.
• Capillary leak syndrome following vaccination with the AstraZeneca Vaxzevria/COVISHIELD COVID-19 vaccine. Health Canada has updated the product monograph to include information on capillary leak syndrome, including a contraindication for patients who have previously experienced this syndrome.
• Facial paralysis/Bell’s Palsy following COVID-19 vaccination. Health Canada has updated the product monograph for both Pfizer-BioNTech Comirnaty and Moderna Spikevax COVID-19 vaccines to include information on facial paralysis/Bell’s Palsy.
• 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.

On September 16, 2021, submissions by the manufacturers under the amended Food and Drug Regulations which include a change to brand names of the Pfizer-BioNTech and Moderna COVID-19 vaccines were authorized by Health Canada. Both vaccines have brand name changes , Pfizer-BioNTech vaccine becoming Comirnaty and the Moderna vaccine becoming Spikevax . The AstraZeneca’s brand name change to Vaxzevria is authorized under the Interim Order. This now reflects new names given by the manufacturers internationally. Get more information about the authorized vaccines:

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

The COVISHIELD version of the AstraZeneca vaccine which provided a temporary supply to Canadians through the Interim Order respecting the importation, sale and advertising of drugs for use in relation to COVID-19 expires with the interim order on September 16, 2021. However, we will continue to monitor for safety.

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: