Researchers at the Emory Rollins School of Public Health, in collaboration with the WHO, UNICEF, and others recently published (July, 2022) a systematic review and meta-analysis on effectiveness of WASH interventions.
This meta-analysis provided up-to-date estimates on the burden of diseases attributed to WASH. The two previous systematic reviews were published in 2014 and 2018. This new systematic-review included 124 studies (83 observations for water, 20 for sanitation and 41 for hygiene).
The main quantitative findings are summarized below:
When compared with unimproved water source, the reduction in risk of diarrhoea were:
- 52% for improved drinking water on premises with higher water quality
- 50% for water filtered at Point-of-Use (POU)
- 21% for basic sanitation without sewer connection
- 47% for basic sanitation with sewer connection
- 30% for hygiene interventions.
Sex-disaggregated data is very limited in WASH context, only 4% of the included studies. (In my opinion, this is a huge data gap).
Highlights, impressions and suggestions from this meta-analysis:
- Drinking water of higher quality and water filtered at POU are effective (up to around 50%) in reducing diarrheal risk.
- Basic sanitation services without sewer connection were associated with a moderate reduction in risk of diarrhoea.
- Sewered sanitation has a greater effect on health than on-site sanitation. (there are several explanations for this suggestion)
- The risk reduction of diarrhoeal disease from handwashing interventions is impressive.
It is an open access paper.
What do you think about their findings? Surprising?
Journal reference:
Wolf, J., et al. (2022) Effectiveness of interventions to improve drinking water, sanitation, and handwashing with soap on risk of diarrhoeal disease in children in low-income and middle-income settings: a systematic review and meta-analysis. The Lancet. doi.org/10.1016/S0140-6736(22)00937-0.