Performance indicators for vaccine safety monitoring systems

Globally there is considerable variation in reporting rates for adverse events following immunization (AEFI) between countries and regions. Currently, a large number of countries report few or no AEFI. There are no globally accepted indicators which could demonstrate the functionality of an AEFI surveillance system. Establishing such indicators is an important element for assessing progress in the development of AEFI surveillance systems. The Global Vaccine Action Plan includes the establishment and strengthening of AEFI reporting as a priority activity for the strengthening of all immunization programmes. There is a need for at least one performance indicator for monitoring progress against that objective.

The intent of AEFI indicators is not to define standards whereby countries can be compared. It is acknowledged that individual countries are at different stages of maturity with regard to AEFI safety systems, that different systems are in place (including the use of different vaccine products) and that it is difficult to capture the complexity and functionality of a system with a single set of indicators. Thus, the primary purpose of the AEFI surveillance indicators will be to provide countries with standards for the evaluation of progress towards functional passive vaccine safety surveillance. The aim will be for all countries to achieve a minimal threshold of AEFI reporting and then to progressively attain one or more of the more advanced indicators. This will allow working targets to be set and to be progressively improved upon.

GACVS considered a number of principles in deriving a set of indicators for AEFI surveillance. Three types of indicators are proposed: (i) to monitor the volume of AEFI reports; (ii) to monitor the quality of those reports; and (iii) to monitor the quality of the response to serious AEFI.

The proposed approach is to establish one single general indicator, accompanied by a number of more advanced indicators. Criteria to define the general indicator are based on principles of simplicity and generalizability. It will assess data already collected by countries which are also reported through the WHO-UNICEF Joint Reporting Form (JRF). The proposed general indicator is the ratio of AEFI reports per 100 000 surviving infants per year.

Advanced indicators are developed with the recognition that countries (and at times regions from large countries) are at different stages of advancement in their AEFI surveillance systems. Countries will be recommended to select one or more advanced indicators and to progressively advance from low to higher levels. A country achieving the highest level of the advanced indicator is considered to have the most advanced AEFI surveillance system. GACVS is pursuing the development of those advanced indicators. This will include piloting testing in countries with different levels of development of their AEFI surveillance systems; when finalized these indicators will be made available through the WHO vaccine safety website.

Full report of GACVS meeting of 3-4 December 2014, published in the WHO Weekly Epidemiological Record of 23 January 2015