Assessment of a Community-Based Surveillance System for Adverse Events Following Immunisation in the Hard-to-Reach Islands of Lake Victoria, Kenya

Robust surveillance for adverse events following immunisation (AEFI) is essential for maintaining public confidence in vaccination programmes. This is particularly challenging in geographically isolated communities with limited health system access, such as the islands of Lake Victoria, Kenya. This brief report assessed the performance of a community-based AEFI surveillance system in these island communities, focusing on key operational attributes. A descriptive assessment used a mixed-methods approach. Data were drawn from routine surveillance reports, key informant interviews with community health volunteers and health facility staff, and focus group discussions with community members. Performance was evaluated against standard criteria including timeliness, reporting completeness, and community awareness. The system achieved high community engagement, with most interviewed caregivers aware of the AEFI reporting mechanism. A key challenge was delayed submission of reports to the district level, primarily due to logistical constraints in transport and communication from the islands. The community-based model is a feasible and acceptable strategy for AEFI surveillance in these hard-to-reach settings, bridging a critical gap in pharmacovigilance. Its strength is high community penetration, though systemic delays in data flow require attention. To strengthen the system, we recommend investing in simple digital reporting tools to accelerate data transmission and providing regular refresher training for community health volunteers on AEFI case definitions and reporting procedures. pharmacovigilance, adverse events following immunisation, community health workers, surveillance, health systems, islands, Kenya This assessment provides evidence for the utility of community-based reporting in extending AEFI surveillance to logistically constrained environments and highlights specific operational barriers that must be overcome.