Vaccine related adverse events

What is an adverse event following immunization (AEFI)?

An AEFI is any untoward medical occurrence which follows immunization and which does not necessarily have a causal relationship with the usage of the vaccine. The adverse event may be any unfavourable or unintended sign, abnormal laboratory finding, symptom or disease.

Why is reporting an AEFI important?

Provincial reporting of an AEFI is an important component of the overall safety assessment of any vaccine. Individual case reports of AEFIs represent an important source of data as they have the potential to generate signals of adverse reactions not previously recognized in clinical studies.

Am I required to report AEFI?

Yes, you are required to report AEFI to your local Medical Officer of Health under Section 38 of the Health Protection and Promotion Act (HPPA) and its accompanying regulation, O.Reg 569 s.7.

What types of AEFI should be reported?

Under the HPPA, Section 38 the following events are considered reportable:

The AEFI Fact Sheet for Health Care Providers (PDF, 300 KB) contains information on the types of adverse events that should be reported.

In general, any adverse event following immunization may be reported to your local Public Health for further follow-up and investigation if:

A causal relationship does not need to be proven, and submitting a report does not imply causality.

If there is any doubt as to whether or not an event should be reported, a conservative approach should be taken and the event should be reported.

What is the Ontario AEFI Reporting Form?

The Ontario AEFI Reporting Form (PDF, 300 KB) is a newly available tool to assist health professionals to report adverse events following immunization to their local public health unit. It replaces the Public Health Agency of Canada (PHAC) Reporting Form previously in use.

The form can be completed electronically and printed or printed and completed by hand. If you choose to complete the form in electronic format, it is important to ensure that you do not leave the computer unattended while you are completing the form. Before leaving the computer, it is also important that you fully exit the application, clear your browser’s cache, and close down your browser. This will ensure that no one else can access any personal health information you may have entered.

Please complete the form with as much detail as possible. In addition to client demographic and immunization information, a detailed description of the event including the following information is essential to be able to provide appropriate advice to vaccine recipients regarding further immunization and contribute towards timely and effective vaccine safety monitoring.

What happens to the information provided on the Ontario AEFI Reporting Form?

Once a reported AEFI is received by the local health unit, it is reviewed and investigated. The local Medical Officer of Health (MOH) may make recommendations to the vaccine recipient/caregiver with respect to additional follow-up and receipt of further doses of vaccine. Public Health Sudbury & Districts enters AEFI reports into the integrated Public Health Information System (iPHIS), the electronic reporting system for reportable diseases and AEFI in Ontario.

Public Health Ontario (PHO) continuously monitors all AEFI reported via iPHIS and transmits to PHAC for inclusion in the Canadian Adverse Events Following Immunization Surveillance System (CAEFISS), a national database containing AEFIs reported from all provinces and territories in Canada.

Once completed, where do I send the Ontario AEFI Reporting Form?

Completed AEFI reporting forms should be sent by secure means to Public Health Sudbury & Districts by secure fax; 705.677.9618. If you have any questions you can speak to a Public Health Nurse by calling 705.522.9200, ext. 301, or toll-free at 1.866.522.9200.

Information for parents/guardians of children receiving vaccination

The AEFI Fact Sheet for Parents (Ministry of Health, PDF, 41 KB) contains information on how to identify and report an adverse event following immunization and can be provided to parents/guardians after a child’s vaccination.


This item was last modified on April 28, 2022