The World Health Organization has released a position paper on the implications of recent WASH (water, sanitation and hygiene) and nutrition studies for WASH policy and practice.
The paper follows the studies’ report of little or no impact from WASH interventions on reducing childhood diarrhoea and stunting in Kenya, Bangladesh and Zimbabwe. As a result, key stakeholders have questioned the value of investing in WASH rather than other public health interventions. The paper notes that WASH is a very broad category of interventions, with different ones more or less appropriate in different settings. The same interventions might have had a greater effect in settings where baseline conditions for WASH and disease were different, it adds – or, conversely, a different package of more ambitious WASH interventions might have had a greater impact in the same setting.
The paper also points out that the studies suggested a number of factors, including poor food hygiene, ineffectiveness of chlorination against some key pathogens, and the short time between interventions and follow-up assessments. WHO says it is likely that the interventions fail to interrupt all pathways for contamination of the environment and so systematically prevent human exposure to faecal pathogens. The paper adds that, unless the intervention achieves a clean environment, a significant reduction in diarrhoea – and, by extension, stunting – is unlikely. It also notes that, given the uncertainty and context specificity of how microbes move in the environment, it may not be realistic to expect health impacts over the timeframe of many trials and programmatic interventions.
WHO concludes: “Overall, the body of evidence indicates a protective effect of sanitation on infectious diseases and nutrition outcomes, and suggests greater impacts when entire community coverage of sanitation is achieved.”