Vaccine pharmacovigilance

The science and activities relating to the detection, assessment, understanding and communication of adverse events following immunisation and other vaccine- or immunisation-related issues, and to the prevention of untoward effects of the vaccine or immunisation (see CIOMS-WHO21).

In this definition, immunisation means the usage of a vaccine for the purpose of immunising individuals (see CIOMS-WHO21 ), which in the EU is preferably referred to as vaccination (in the report of CIOMS/WHO Working Group on Vaccine Pharmacovigilance the terms immunisation and vaccination are used interchangeably 21 ). Usage includes all processes that occur after a vaccine product has left the manufacturing/packaging site, i.e. handling, prescribing and administration of the vaccine (see CIOMS-WHO21 ).

An adverse event following immunisation (AEFI) is any untoward medical occurrence which follows immunisation 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. While this AEFI definition is compatible with the definition of adverse event applied in the EU, the AEFI definition is not needed to describe pharmacovigilance for vaccines in the EU. However, EU guidance on pharmacovigilance for vaccines makes use of the terminology suggested by CIOMS-WHO21 regarding possible causes of adverse events, turning them into suspected adverse reactions. A coincidental event is an AEFI that is caused by something other than the vaccine product, immunisation error or immunisation anxiety (see CIOMS-WHO21 ).

See also Adverse event, Vaccine product-related reaction, Vaccine quality defect-related reaction, Immunisation error-related reaction, Immunisation anxiety-related reaction, Immunisation stressrelated response, Vaccination