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Vaccine Safety

Ontarians can be confident. Standards of safety, efficacy, and quality have not been compromised to expedite the approval of COVID-19 vaccines.

As with all approved vaccines and treatments, Health Canada oversight of COVID-19 vaccines does NOT stop at approval. Monitoring of the vaccine’s safety and effectiveness will continue now and into the future.

How can a vaccine be developed so quickly?

We have seen the development of vaccines for COVID-19 happen quickly. While this has happened faster than usual, the safety of the vaccine is not compromised.

The Interim Order establishes regulatory procedures to accelerate the authorization of COVID-19 drugs during a public health emergency, while maintaining all the requirements for the health and safety of Canadians.

Health Canada has put in place a fast-tracked review process to assess COVID-19 vaccines. If manufacturers apply through the interim order process, Health Canada can start the review process right away. Health Canada is also able to review any new evidence as it becomes available, instead of waiting until all studies are completed. More scientific resources have been dedicated to completing these reviews so that they're done quickly but without cutting corners.

A similar process was used in 2009 for the review and authorization of the H1N1 influenza pandemic vaccine

The development and approval of vaccines for COVID-19 progressed quickly for many reasons:

  • The vaccine approval process did not experience any time delays
  • Researchers had already begun extensive studies on mRNA and other viral-vector-based technology. This has allowed researchers to quickly adapt research that was already completed. To date, mRNA has been successfully used in cancer treatments, and research into its value for vaccinations has been ongoing for over ten years
  • During this process we have seen people from all over the world work together with a shared goal (scientists, health professionals, researchers, industry and governments)
  • Recruiting participants for the clinical trials was a quick process
  • The clinical trials were set up quickly and demonstrated effectiveness of the vaccine

Vaccines used in Canada are highly effective and extremely safe. Vaccines are among the safest medical products available. We have a strong monitoring system for drug safety in Canada.

For more information on vaccine safety, visit

In Canada, who determines that vaccines are safe?

  • At the federal level, Health Canada and the Public Health Agency of Canada (PHAC) share the responsibility for ongoing monitoring, which also involves provincial, territorial and local public health authorities, health care professionals, the vaccine industry, international regulators and the public.
  • Health Canada supervises all aspects of vaccine production by manufacturers to ensure safety, efficacy and quality. Vaccine safety continues to be rigorously monitored and evaluated after the vaccine is on the market.
  • Prior to authorization for use in Canada, vaccines are extensively tested and the manufacturer must submit scientific and clinical evidence that demonstrates the safety and efficacy of the vaccine.
  • Health Canada also reviews the data to assess the benefits and risks of the vaccine. As for all vaccines and treatments that are authorized in Canada, Health Canada decides whether to authorize the COVID-19 vaccine and will only do so when the data shows that the vaccine:
    • is safe, effective and of good quality, and
    • demonstrates that the benefits outweigh the risks
  • Even after vaccine approval, your health care team will continue to assess vaccine safety. Your health care team (nurses, doctors and pharmacists) will report any side effects or safety concerns.
  • On December 9, 2020, Health Canada authorized the first COVID-19 vaccine in Canada, manufactured by Pfizer-BioNTech. On December 23, 2020, approval was granted for use of the Moderna vaccine. Health Canada authorized the vaccines after an independent and thorough scientific review for safety, effectiveness and quality. Health Canada will continue to monitor the safety and effectiveness of the vaccines.

Vaccine Safety Is ALWAYS an Ongoing Process

Pre-market scientific review (prior to approval)

  • Must demonstrate that the vaccine can protect against disease
  • Safety and efficacy reviews are completed
  • Confirm that benefits outweigh the risks
  • Confirm there are no safety concerns
  • A plan is put into place that will minimize any potential risks associated with immunization (i.e. requirement to report adverse events to Health Canada)

Post Market Surveillance (ongoing surveillance)

There are many agency’s and health care professionals that are involved in the ongoing surveillance of the vaccine’s safety:

Heath Care Providers

  • Will report any adverse events to their local Health Unit

Provincial and Territorial Public Health Authorities

  • Will report to PHAC’s surveillance system. Public Health Ontario’s program leads the surveillance of adverse events following immunization in Ontario

Health Canada

  • Will continue to monitor safety and effectiveness of vaccines authorized for sale in Canada
  • Determine need for further plans to minimize potential risks and additional safety information from the vaccine manufacturer
  • Monitors vaccine-related events in Canada and internationally

Public Health Agency of Canada

  • The Canadian Adverse Events Following Immunization Surveillance System (CAEFISS) is managed by PHAC and is an FPT post-market vaccine safety monitoring system that includes spontaneous, enhanced and active AEFI reporting processes


  • Responsible to monitor the safety and effectiveness of their products (i.e., Pfizer-BioNTech is conducting clinical trials and will continue to follow their participants for at least two years)
  • If any concerns arise, the manufacturers are legally required to inform Health Canada

Vaccine safety resources

The following are some key trusted resources to support public health and health care provider communication about the vaccine safety surveillance system:

Canadian Adverse Events Following Immunization Surveillance System (CAEFISS) -
Public Health Agency of Canada

Canadian Immunization Guide: Part 2 - Vaccine Safety -
Public Health Agency of Canada

Canada’s eight-component vaccine safety system: A primer for health care workers | Canadian Paediatric Society (
Canadian Paediatric Society

Vaccine Safety | Public Health Ontario
Public Health Ontario

Vaccine Safety Surveillance Tool | Public Health Ontario
Public Health Ontario

Reports of myocarditis/pericarditis after COVID-19 vaccination: FAQ for health-care providers

COVID-19 Vaccine Safety Post Market Surveillance

COVID-19: Vaccine safety and side effects -

COVID-19 vaccine safety: Weekly report on side effects following immunization -

Government of Canada

Can vaccines cause Autism?

No. Vaccines do not cause autism. Researchers and scientists around the world have proved that there is no link between autism and vaccines.