Barriers in operating proactive source reduction informed by an early warning system for dengue prevention: A qualitative study from end-user perspectives in Vietnam.

BACKGROUND: Dengue is a major vector-borne disease, with rising incidence driven by climate change, rapid urbanization, and increased international travel. Although early warning systems (EWSs) have shown promising predictive performance in endemic settings, limited evidence on implementation barriers from local end users hinders their integration into routine proactive vector control. METHODS: A qualitative study with in-depth interviews was conducted with local end users, including local authorities, health practitioners, and health volunteers. A deductive approach utilizing a predefined conceptual framework was employed to code the verbatim transcripts. Inductive coding was subsequently incorporated to capture emerging concepts that were not represented in the initial framework. Thematic analysis was performed to analyse the collected data. To enhance the methodological rigor, interviews and coding were performed by multiple and diverse researchers from various academic and practice institutions, and the transcripts were validated through member checking with selected participants. RESULTS: The lack of supportive policies, limited engagement from relevant stakeholders due to low familiarity with EWS concepts, and operational challenges were identified as critical barriers to implementing EWS-informed proactive source reduction. The perception that dengue risks were only during the rainy season, together with socio-economic constraints, water scarcity exacerbated by extreme weather events, and the application of inappropriate source reduction measures, further constrained household participation. The multi-level barriers collectively disrupted the translation of EWS alerts into proactive dengue prevention. CONCLUSIONS: Early warning information alone is insufficient to translate into effective and sustained proactive vector control for dengue prevention. Strengthening enabling policies, local stakeholder and community engagement, and awareness of EWS-informed risk management across multiple levels are essential to translate EWS alerts into timely and sustained vector control actions in dengue-endemic settings similar to Vietnam. Further studies across diverse settings are needed to assess the broader applicability of EWS-informed approaches.