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.
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.
Annual Report on Vaccine Safety in Ontario, 2018