Vaccine safety surveillance is essential to the success of immunization programs.
PHO leads the provincial surveillance of adverse events following immunization (AEFIs). An AEFI is an unwanted or unexpected health effect that happens after someone receives a vaccine, which may or may not be caused by the vaccine.
In Ontario, health professionals are required to report AEFIs to their local public health unit. Public health units investigate AEFIs and provide support to immunizers, individuals, and their families.
If you experience an adverse event after immunization, please contact your health care provider.
For information specific to COVID-19, please visit the COVID-19 Vaccine webpage.
Public Health Ontario is a member of Vaccine Safety Net – a global network of websites, evaluated by the World Health Organization, that provides reliable information on vaccine safety.
Vaccine Safety in Ontario, 2019
Ongoing surveillance of adverse events following immunization (AEFI) is essential for monitoring vaccine safety and maintaining confidence in immunization programs. The following resources provide a summary of AEFIs reported in Ontario following vaccines administered in 2019, as well as trends comparing AEFIs reported across eight years between 2012 and 2019.