National AEFI surveillance systems
National Regulatory Authority (NRA), Pharmacovigilance Center (PVC) and National Immunization Programmes (NIP) are responsible for developing and maintaining a national AEFI surveillance system. Often an AEFI review committee and other support groups such as academic institutions and technical agencies are linked to the AEFI surveillance system. In countries that produce their own vaccines, vaccine manufacturers and national control laboratories may be part of the national AEFI surveillance system.
AEFI surveillance addresses the needs of NIP, NRA and PVC. The general principles of AEFI surveillance are:24
- detection, correction and prevention of immunization errors;
- identification of potential problems with specific vaccine lots;
- prevention of false blame from coincidental events;
- maintenance of confidence in the programme by properly responding to parent/community concerns;
- identification of signals for unexpected adverse events and generation of hypotheses to be tested by controlled studies;
- estimation of AEFI rates in local populations;
- support to formulate and adjust contraindications, risk/benefit equations, and provider and patient information.
Mass vaccination campaigns
An area of specific need are mass vaccination campaigns. During campaigns, a large number of doses are administered over a short period. There is a high probability of coincidental adverse events. Immunization errorsImmunization errorAn AEFI classification that refers to events caused by errors in vaccine preparation, handling, or administration. may occur if vaccines are not being given by those who regularly administer vaccine. During campaigns there is also often increased awareness towards an apparent rise in reported adverse events, which can undermine the confidence in the vaccine being used and can have a major impact on the success of the campaign.
General principles of AEFI surveillance are similar in all countries. However, approaches may differ because of factors such as the organizational structure of immunization services and the amount of resources available.
National AEFI surveillanceAEFI surveillance (also known as vaccine safety surveillance)A surveillance system designed to collect adverse events temporally associated with receipt of vaccines. This type of surveillance typically relies on health professionals associating an adverse event in an individual as a possible consequence of vaccination and reporting it to the NRA or appropriate authority. should be carried out in close collaboration with the NIP, NRA, PVC, AEFI review committee, and other support groups (i.e. technical agencies and academic institutions). In countries that produce their own vaccines, vaccine manufacturers, and national control laboratories should be involved in AEFI surveillance.