Coincidence analysis: Identifying factors contributing to frontline health workers’ confidence to face future pandemics across Honduras, Syria, and South Sudan

Frontline health workers in humanitarian settings play a critical role in pandemic response, yet evidence on what sustains response readiness beyond the emergency is limited. This study examined factors associated with primary healthcare workers' sustained self-reported knowledge, skills, and confidence to respond to future outbreaks or pandemics, with the configurational analysis focused on confidence. A retrospective cross-sectional survey was conducted among 118 health workers in Honduras, Syria, and South Sudan who received COVID-19 training. Coincidence analysis was applied with a set of associated predictors to identify combinations of conditions linked to high sustained confidence. COVID-19 training that covered five or more core topics was associated with high sustained self-rated capacities; topics included proper use of personal protective equipment, transmission routes, procedures for case screening, and facility infection prevention and control. Continuity of primary healthcare services after emergency funding ended, fewer disruptions from conflict or natural disasters, and supportive team structures were linked to confidence. Coincidence analysis indicated multiple sufficient causal pathways to sustained confidence, the first being very high self-rated post-training knowledge as a standalone pathway (consistency: 0.66, coverage: 0.62). Other pathways included health workers with higher education combined with either case-screening training or working in facilities that continued services post-funding (consistency: 0.604, coverage: 0.64). Applying COVID-19 practices to other outbreaks (e.g., dengue, cholera) further reinforced capacities and illustrated the pathogen-agnostic value of core infection prevention and response competencies. Results underscore that durable preparedness at the primary healthcare level in fragile contexts depends on comprehensive, practice-oriented training for all types of frontline health workers, as well as enabling conditions that maintain service delivery. This study contributes to emerging literature using implementation science frameworks and coincidence analysis to understand complex causal pathways. The findings should inform global health security investments, including in the world's most fragile health systems.