Immunization safety surveillance

Vaccines are considered drugs but require different immunization safety surveillance systems to monitor adverse events.

Immunization safety is the process of ensuring and monitoring the safety of all aspects of immunization, including:

• vaccine quality, 
• adverse events, 
• vaccine storage and handling, 
• vaccine administration, 
• disposal of sharps,
• management of waste.

The skills and infrastructure to deal with genuine vaccine adverse reactions are essential to public safety, as well as to prevent or manage fear caused by false or unproven signals from patients and health workers. 

Why the need for specific adverse event following immunization (AEFI) surveillance?

Because,

1. Vaccines are usually received by healthy people including infants. 8–15 Childhood vaccines are globally recommended. 
2. Often received by most of the population, birth cohort, or group at high risk for disease or complications.
3. Vaccines are taken to prevent disease
4. Subpopulations may be more susceptible to experience certain AEFIs.
5. The age at the time of immunization may coincide with the emergence of certain age-related diseases (e.g. neurodevelopmental disorders).
6. Immunization with certain vaccines is mandated in some countries.

The Council for the International Organizations of Medical Sciences (CIOMS) and WHO established a joint working group on vaccine pharmacovigilance in 2005, recognizing that vaccines represent a special group of medicinal products with issues specific to the monitoring and assessment of vaccine safety.

The objectives for an effective AEFI surveillance system are to:

• Identify problems with vaccine lots or brands leading to vaccine reactions caused by the inherent properties of a vaccine,
• Detect, correct and prevent immunization errors caused by errors in vaccine preparation, handling, storage or administration,
• Prevent false blame arising from coincidental adverse events following immunization, which may have a known or unknown cause unrelated to the immunization,
• Reduce the incidence (number of new cases (e.g., of a disease, adverse event) occurring in a defined population during a given time interval, often one year) of injection reactions caused by anxiety or pain associated with immunization, by educating and reassuring vaccinees, parents/guardians and the general public about vaccine safety,
• Maintain confidence by properly responding to parent/community concerns, while increasing awareness (public and professional) about vaccine risks,
• Generate new hypotheses about vaccine reactions that are specific to the population of your country/region,
• Estimate rates of occurrence of AEFIs in the local population compared with trial and international data, particularly for new vaccines that are being introduced.

Components of AEFI surveillance:

• Detection and reporting,
• Investigation,
• Causality assessment of AEFIs,
• Risk/benefit assessment.