An Evaluation of the Surveillance System for Monitoring and Reporting Adverse Events Following Immunization in Kebbi State, Northern Nigeria: A Mixed Method Approach

"The...issues have actively undermined the effectiveness of AEFI detection, reporting, and documentation, thus impeding the capacity of the system to generate robust and high-quality data to inform vaccine safety considerations and generate sufficient demand for immunization."

An adverse event following immunisation (AEFI) is any untoward medical event that occurs following immunisation and does not necessarily have a causal relationship with vaccine usage. Nigeria is one of the countries within the African region with low or sub-optimal reporting of AEFIs. This study evaluated the AEFI surveillance system in Kebbi State, Nigeria, to ascertain the system's functionality to inform vaccine safety considerations and guide communication strategies for demand generation.

The paper begins with an overview of the AEFI surveillance reporting system in Kebbi State, where 660 health facilities (HFs) render routine immunisation (RI) services. In brief, at the HF level, a trained RI provider is in the custody of the various AEFI data tools and does the documentation and archiving. There are two channels for the AEFI data management system: Integrated Disease Surveillance and Response (IDSR) and District Health Information System 2 (DHIS2).

The study employed a mixed-methods approach. Based on the grounded theory approach, the researchers conducted 10 key informant interviews (KIIs) and two sessions of focus group discussions (FGDs) with senior officers and managers at sub-national and national levels within the immunistion and surveillance landscape in Nigeria. Survey questionnaires were administered to 274 RI service providers, who were asked eight questions/items on simplicity, six questions on flexibility, three questions on data quality, timeliness, and stability, four questions on acceptability, and two questions on representativeness and completeness. In addition, the researchers reviewed timeliness and completeness data for AEFI reports in the State over three years.

Of the respondents, 201 (73.4%) reported that the surveillance system can inform vaccine safety considerations, while 170 (62%) reported that the AEFI surveillance system can determine the magnitude of AEFIs within the population. Further, 173 (63%) reported that the surveillance system can provide timely feedback about causality assessment. However, only 158 (58%) of the respondents stated that the surveillance system is competent in informing communication strategies to improve immunisation demand. Most of the interviewees indicated that the system is ineffective in driving demand for AEFI reporting itself.

Overall, the surveillance system can be said to be simple, flexible, and acceptable based on the responses given by the participants. The surveillance system is largely representative of the AEFI cases, and the data quality can be best described as fair. Based on the analyses of participants' responses, the timeliness of reporting is poor, and the stability or resilience of the AEFI is weak (poor). There is a convergence of opinions of the participants that the surveillance system is sub-optimal regarding sensitivity, given that there is a high degree of under-reporting, delayed, or non-transmission of reports (data) to the next level and incomplete documentation of AEFI cases. Evidence from the qualitative interviews also indicated that health workers have lackadaisical attitudes towards AEFI reporting and community awareness about AEFI, and its reporting is low.

Finally, the study unearthed some underlying health system factors impeding the AEFI surveillance system from fully fulfilling its objectives. Challenges associated with the operationalisation of AEFI in Nigeria include human resource deficit, comparatively less attention being paid to AEFI surveillance as compared to acute flaccid paralysis (AFP) and vaccine-preventable disease (VPD) surveillance driven by partners and donor funding, data tool inadequacy, and limited knowledge of case definitions of AEFI and the procedures for causality assessment. Roughly half of the respondents reported that new procedures and restructuring affect AEFI surveillance.

In conclusion: "The AEFI surveillance system in Northern Nigeria is well established but functioning sub-optimally. Based on the study findings, the capacity to provide information on vaccine safety exists but it is not robust enough to generate sufficient and convincing vaccine safety data and guide communication strategies for vaccine demand generation, especially for new vaccines and those under emergency authorization use....Addressing the health system challenges and specific operational bottlenecks would improve AEFI surveillance and documentation in Kebbi State and possibly, the entire Nigeria."