7.5  Adverse events following immunization (AEFIs)

An adverse event following immunization (AEFI) is the term used to describe any adverse event that takes place after immunization, which may or may not be caused by the immunization. There are five categories of AEFIs defined in Table 7.1 below.

Table 7.1 Categories of adverse events following immunization (AEFIs).
Adverse eventsDescription
Vaccine reactionEvent caused or precipitated by the vaccine when given correctly, and due to the inherent properties of the vaccine
Programme errorEvent caused by an error in vaccine preparation, handling or administration
Coincidental eventEvent that happens after immunization but is NOT caused by the vaccine, i.e. it is a chance association
Injection reactionEvent caused by anxiety about, or pain from, the injection itself rather than the vaccine
Unknown causeEvent for which the cause cannot be determined despite thorough investigation

7.4  Contraindication to immunization

7.5.1  Mild reactions to vaccines