Effectiveness of stand-alone and multi-component water, sanitation and hygiene interventions to reduce mortality in childhood: a network meta-analysis

Abstract Mortality in childhood constitutes the vast majority of the global burden of disease due to diarrhoea and respiratory infection, which is closely related to water, sanitation and hygiene (WASH) use by households. Here we use a component network meta-analysis to evaluate the comparative effectiveness of stand-alone and multi-component WASH interventions in reducing all-cause mortality in childhood in low- and middle-income countries. We find that interventions improving water supplies in quantity and drinking water are associated with reductions in all-cause mortality. Furthermore, we find that, when initial water supplies are improved, hygiene and sanitation interventions are more effective, suggesting that having enough water for washing enables better hygiene and defaecation practices. We also find that WASH packages are less effective than stand-alone interventions and that there are no synergies between interventions. On the contrary, we find some evidence of antagonistic interactions, particularly among interventions with intensive behaviour change components. These findings caution against the implementation of multi-component interventions and also favour prioritizing approaches that improve water supply conditions first. We highlight coordination problems and conflicts between the behavioural changes promoted by the interventions as potential causes of antagonistic interactions.