Core variables for AEFI monitoring
Collection of harmonized data on AEFI allows for better comparison and pooled analysis with findings from vaccine safety surveillance systems. In collaboration with a network of countries and independent experts, a preliminary list of core variables had been proposed. This list was subsequently compared with the reporting forms from the WHO Programme for International Drug Monitoring (Uppsala Monitoring Centre) to verify which variables are captured by the current reporting forms. Through this exercise, it became apparent that vaccine safety monitoring needs tools which are more specific to the type of variables required for proper AEFI surveillance and that the current web-based interface developed for reporting of suspected drug reactions (VigiFlow) should be adapted for AEFI reporting. To address these issues, the GACVS in December 2011 suggested developing a simpler and vaccine-specific user interface to enter AEFI data. A subgroup of GACVS was tasked to address those issues and presented the status of ongoing activities at the June 2012 meeting.
Collection of basic and advanced AEFI information
It is recognized that for the purpose of signal detection, data collection tools should remain as simple as possible. However, when signals are detected, or in cases of serious AEFI, additional data are essential to allow inferences to be drawn on the association with vaccines and to assess the need for further investigation and action. The subcommittee presented GACVS with 22 core variables that should be collected for any AEFI (basic information) and an additional 33 variables of interest for a more detailed case review (advanced information). Basic information collected needs to be prioritized because the AEFI data collection, collation, transmission, analysis and feedback systems in different countries are heterogeneous. In addition, quantitative and qualitative aspects of data need to be considered. The suggested approach proposes a basic minimum of 22 variables with 10 identified as critical. This simple structure is expected to encourage countries that do not yet have an AEFI surveillance system in place to develop one. It is proposed that the reporting tool include the WHO-ART dictionary in order to standardize the terminology used to record signs, symptoms or a diagnosis, as well as a vaccine dictionary that will include details pertaining to all of the vaccines suspected. For the advanced information, details on the nature and frequency of reporting for events such as in campaigns or in routine immunization programmes, breast or bottle feeding, status of previous vaccination are proposed.
“VacciFlow” will be developed as the adaptation of drug-specific VigiFlow 4.2 to facilitate the entry of vaccine-related AEFI data including immunization programme errors. Ideally “VacciFlow” will be used by both the national regulatory authority and the immunization programme staff. The possibility of incorporating this new interface with minimal computer capabilities and mobile phone technology was encouraged by GACVS. There will be 3 flexible levels created in “VacciFlow” enabling national and subnational level users to analyse and use the data available for action at each level. Automatic feedback to reporters on the status of the report will be built in. Adapting (modifying) existing AEFI reporting systems to adjust to the data proposed in this core set of variables will require an educational and dissemination effort in many countries. It is expected that the upcoming “VacciFlow” will be sufficiently simple and user-friendly to allow tailor-made adjustment for locally collected information.