Syndromic surveillance in displacement settings: a two-year evaluation of a community-reporting system in northern Lebanon

Abstract

Formal disease surveillance rarely reaches displaced populations, whose health infrastructure is fragmented and whose movement patterns defeat catchment-based reporting. We evaluated a community-reporting syndromic surveillance system operating across fourteen informal settlements in northern Lebanon between 2023 and 2025, covering approximately 31,000 residents. Trained community reporters submitted weekly syndrome counts by mobile phone; these were compared against clinic-confirmed diagnoses from partner primary health centres. The system detected 8 of 11 confirmed outbreak events, with a median lead time of 9 days over clinic-based detection, and a false-positive rate of 0.7 alerts per settlement-year. Sensitivity was highest for acute watery diarrhoea and lowest for acute jaundice syndrome. Reporter attrition, at 22% annually, was the principal operational constraint and correlated strongly with the interval between stipend payments.