Handwashing promotion and childhood diarrhea in Pakistan. Reply [letter]

Dr Mujeeb argues there was no equipoise for the Karachi Soap Health Study because public health scientists already know that handwashing reduces diarrhea. However the degree of diarrhea reduction that can be achieved with intensive handwashing in highly contaminated settings especially among children at highest risk of death is not well established. Indeed as noted in our article there has been substantial methodological criticism of the prior studies on handwashing. If handwashing is going to be advocated for prevention of diarrhea it is important to understand the degree of its effectiveness. The study used a standard habits and practices population as a control because this was the comparison that would answer the relevant question ie what is the maximum benefit that can be achieved with an intensive handwashing promotion campaign in a highly contaminated setting? This control group already did purchase and use soap routinely. Having a control group that was given intensive promotion messages but no soap would answer a different question ie how important is the provision of free soap for handwashing promotion? This only becomes an important question once the overall magnitude of the health benefit is clear. (excerpt)