Effectiveness of Water, Sanitation, and Hygiene (WASH) Interventions in Humanitarian Settings: A Meta-Analysis of Diarrheal Disease Reduction

Abstract

Abstract:
Water, sanitation, and hygiene (WASH) interventions are essential for reducing disease burden in humanitarian emergencies. Diarrheal diseases contribute to 30–50% of child mortality in displacement settings. This meta-analysis includes 24 studies involving 188,000 participants across 14 countries between 2010 and 2023. Findings show WASH interventions reduce diarrheal disease incidence by 39% (RR: 0.61; 95% CI: 0.54–0.70). Chlorinated water supply led to a 45% reduction, while hand hygiene education reduced incidence by 32%. Camps with ≥75% safe water coverage had a 51% decrease in diarrheal cases compared to 19% in low-coverage camps. However, 41% of interventions lacked long-term monitoring. Only 37% distributed hygiene kits, and latrine-to-user ratios averaged 1:76, exceeding SPHERE standard (1:50). The study recommends improved hygiene promotion, timely latrine construction, and quality water monitoring to achieve sustainable outcomes.