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Adverse Events Following Immunization

An adverse event following immunization (AEFI) is any untoward medical occurrence in a vaccinee that follows immunization. It does not necessarily have a causal relationship with the vaccine or the immunization process.

For the criteria for the reporting of adverse events, and for help with the interpretation of adverse events following immunization and their implications for subsequent immunization, see Part 5 of the BC Immunization Manual: Adverse Events Following Immunization.

Criteria for reporting an adverse event

As of January 1, 2019, a health professional who is aware of an adverse event following immunization must report the event to the medical health officer as per the Reporting Information Affecting Public Health Regulation, Part 2, Division 1, Section 5 of the Public Health Act.

Events that must be reported include:

  • serious events (life-threatening or resulting in death, requiring hospitalization, resulting in a residual disability, associated with congenital malformation)
  • events requiring urgent medical attention
  • unusual or unexpected events (for example, an event that has not been identified previously or has been identified before but is occurring with greater frequency in the population)
  • clusters of events: known or new events that occur in a geographic or temporal cluster (for example, 6 in a week or 6 in a single Health Service Delivery Area)

Events that should not be reported:

  • local injection site reactions and non-specific systemic reactions (for example, headache, myalgia) unless these are more frequent or severe than expected based on clinical trial findings (However, always counsel clients about expected reactions following immunization and how to manage these reactions.)
  • events that have another obvious cause (for example, co-existing conditions)

How to report an AEFI

If your patient experiences an adverse event

  1. Download the Adverse Event Following Immunization case report form 
  2. Refer to the AEFI user guide for instructions on how to complete the AEFI case report form
  3. Complete the form and print it 
  4. Mail or fax the completed, printed form to your local health unit in your health authority
  • First Nations Health Authority – send to the local unit of the vaccine recipient’s home address  Questions? Email:
  • Fraser Health Authority – public health units 
  • Interior Health – health centres 
  • Island Health – health unit locations 
  • Northern Health – mail or fax to: Communicable Disease Hub, 101-155 McDermid Drive, Prince George, BC V2M 4T8, Fax: 250.649.7071 | Questions? Phone: 250-565-2990
  • Vancouver Coastal Health – immunization clinics 

Don’t know which health authority you are in? Find your location on the map of where to report adverse event following immunization

If you observe or treat an anaphylactic episode

Anaphylaxis is an adverse event, a very rare but potentially life-threatening reaction to immunization. Healthcare providers who observe or treat an anaphylactic episode are asked to complete a worksheet in addition to the AEFI form. The information in the worksheet can be used to help complete the AEFI form. 

  1. Download the Worksheet for Events Managed as Anaphylaxis Following Immunization  
  2. Complete and print the form. 
  3. Use the worksheet to complete the AEFI form and report the AEFI to the the local health unit as outlined above.
For a decision tool, with immunization-specific information, including background information and reporting regulations, see Part 3 of the BC Immunization Manual: Management of Anaphylaxis in a Non-Hospital Setting.

SOURCE: Adverse Events Following Immunization ( )
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