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How effective is hand washing in preventing spread of diarrhoea?

Summary of a new Cochrane review that could be relevant to your next consultation

Summary of a new Cochrane review that could be relevant to your next consultation

Diarrhoea is a common cause of morbidity, transmitted by ingesting contaminated food or drink, by direct person-to-person contact, or from contaminated hands. Some studies have estimated that 70% of all cases of diarrhoea can be attributed to food and water contaminated by faeces.

Hand washing is one of a range of hygiene promotion interventions that can interrupt the transmission of diarrhoea-causing pathogens.


The objective was to evaluate the effects of interventions to promote hand washing on diarrhoeal episodes in children and adults. We searched for randomised controlled trials, where the unit of randomisation is an institution (such as a day-care centre), household or community, that compared interventions to promote hand washing or a hygiene promotion that included hand washing with no intervention to promote hand washing.

Two authors independently assessed trial eligibility and methodological quality. Where appropriate, incidence rate ratios (IRR) were pooled using the generic inverse variance method and random-effects model with 95% confidence intervals (CI).


Fourteen randomised controlled trials met the inclusion criteria. Eight trials were institution based, five were community based, and one was in a high-risk group (AIDS patients). Interventions promoting hand washing resulted in a 29% reduction in diarrhoea episodes in institutions in high-income countries and a 31% reduction in such episodes in communities in low- or middle-income countries.

Authors' conclusions

Hand washing can reduce diarrhoea episodes by about 30% – suggesting less benefit than was reported by previous reviews of hand washing and other hygiene interventions, which estimated reductions of 47% and 44% respectively.

The risk reduction in community-based studies was 31%, compared with 29% for institution-based studies.

Trials with longer follow-up and that test different methods of promoting hand washing are needed.

The challenge is to find effective ways of getting people to wash their hands appropriately.

The Cochrane Library contains high-quality, independent evidence to inform healthcare decision making. Cochrane Reviews represent the highest level of evidence on which to base clinical treatment decisions. The Cochrane Library contains thousands of answers to healthcare questions.

It is published by Wiley-Blackwell for the Cochrane Collaboration Cochrane Collaboration (, a UK-registered international charity, providing up-to-date information about the effects of healthcare. The Cochrane Library is available free for all UK residents thanks to funding provided by official sources. See Access to Cochrane for details. For more information contact

Hand washing

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