Joseph_M.

Water, sanitation, and hygiene (WASH) interventions are key to reducing the burden of disease associated with outbreaks, and are commonly implemented in emergency response. However, there is a lack of summarized evidence on the efficacy and effectiveness of these interventions. We conducted a systematic review of published and grey literature by developing theory of change models, developing inclusion criteria, conducting the search, selecting evaluations for inclusion, assessing the quality of the evidence, and analysing the included evaluations.

This evidence synthesis identifies, synthesizes and evaluates existing evidence of the impacts of water, sanitation, and hygiene (WASH) interventions in disease outbreaks in 51 humanitarian contexts in 19 low and middle-income countries. The research team developed theories of change for the WASH interventions under consideration, documenting the theoretical route from intervention activities to outputs, outcomes, and impacts. WASH interventions consistently reduce both the risk of disease and the risk of transmission in outbreak contexts.

There are increasing numbers of people affected by natural disasters, disease outbreaks, and conflict. Water, sanitation, and hygiene (WASH) interventions are used in nearly all emergency responses to help reduce disease risk. However, there is a lack of summarized evidence on the efficacy and effectiveness of these interventions.