Vaccine safety
Reporting an adverse event following immunization (AEFI)
An adverse event following immunization (AEFI) is any unwanted or unexpected health event that occurs after someone receives a vaccine. The event may or may not be caused by the vaccine.
Health care providers are required by law to report AEFIs to their local public health unit. Vaccine recipients or their caregivers can also voluntarily report AEFIs to public health.
If a patient is showing signs of having an adverse reaction after being given a vaccine, including COVID-19 vaccines:
- Complete an adverse event following immunization reporting form from Public Health Ontario.
- Fax the completed form to Peel Public Health at 905-565-0426.
Common or mild events, such as a fever or local injection site reactions, or events that are clearly attributable to other causes, do not need to be reported.
For more information on AEFIs and how to report to public health, refer to vaccine safety from Public Health Ontario, which includes an AEFI reporting fact sheet for health professionals.
Additional resources
Refer to additional fact sheets and handouts about vaccine safety:
Vaccine safety – Public Health Agency of Canada
Resources for health professionals on surveillance, reporting and regulation.
The immunization well-child toolkit – Ministry of Health
Handouts and fact sheets to share with parents about vaccine safety, including the importance of vaccines, tips for a positive vaccination experience, if they choose not to vaccinate their child, and more.