Flood preparedness and public health policy, Greece.

Floods are among the most frequent and complex climate-related hazards, affecting health and health systems through infectious disease risks, water and chemical contamination, and disruption of essential services. Examining how international guidance reflects the operational realities of flood response, and how it supports countries in practice, is essential. While each event is unique, sharing experiences can strengthen preparedness and resilience. This paper draws lessons from an assessment of the response measures used during the 2023 floods in Greece. The coordination team rapidly adapted existing structures for infectious disease surveillance, vaccination and water quality monitoring to an emergency response of exceptional scale. To track flood-related diseases, the coordination team reconfigured syndromic surveillance tools initially designed for refugee camps, and compared proportional morbidity with baseline data to provide early warnings. The team also implemented multiplex polymerase chain reaction diagnostics and mobile vaccination campaigns targeting high-risk groups. Risk communication and community outreach combined repurposed materials with new flood-specific guidance. While there were no outbreaks of gastroenteritis, respiratory infections or mosquito-borne diseases, 45 leptospirosis cases and one fatal non-toxigenic Vibrio cholerae infection highlighted the need for sustained vigilance. The lessons learnt indicate that preparedness relies on flexible adaptation of existing systems, cross-governmental coordination and active community engagement. Gaps in global and regional guidance, especially regarding laboratory diagnosis, safe water restoration and chemical safety monitoring, complicate field decision-making. Strengthening international frameworks, embedding flood preparedness within climate adaptation strategies and applying One Health approaches are therefore critical to ensure health system resilience as flood events become increasingly frequent and severe.