Climate change, hygiene, and health: a research roadmap for climate adaptation

Climate change is intensifying hazards that threaten population health, including those that undermine hygiene behaviours, services, and infrastructure. While water and sanitation feature in climate-health agendas, hygiene, and the behaviours and enabling conditions that interrupt disease transmission, remains under-specified. We identified critical research priorities at this intersection through a structured, consensus-driven process involving global experts. Using the Child Health and Nutrition Research Initiative (CHNRI) method, we generated potential research questions via a rapid scoping review and key informant interviews. After screening and refinement, 57 questions were classified using the "4Ds" framework (description, delivery, development, discovery) and scored by global stakeholders against four weighted criteria: relevancy, answerability, potential impact, and potential for translation. The multilingual survey was disseminated globally and completed by 141 respondents from 40 countries representing academic, non-governmental, multilateral, and government sectors. The top 20 research priorities spanned all aspects of hygiene and climate-related hazards and impact drivers, with 75% focussing on descriptive research to quantify disease burdens, understand hygiene practices and coping strategies under climate stress. Climate-related hazards, such as extreme weather events, dominated the questions (55%) with water scarcity as the second most frequently cited climate impact driver. Delivery-focused priorities (20%) addressed preparedness strategies, targeted support for vulnerable groups, and hygiene promotion during hazards. Only one top-ranked question related to intervention development. Equity considerations, particularly for people with disabilities, women, and girls, featured prominently. This research agenda addresses a critical gap in climate-health priorities by explicitly linking climate hazards to hygiene practices, infrastructure, and behaviour change needs. By directing attention and resources to these priorities, we aim to guide future research investments, inform policy, and support programming responsive to climate-driven hygiene challenges. The agenda complements global initiatives on climate and health, emphasising the need for evidence-based strategies to safeguard health in an increasingly unstable climate.