What can hand hygiene do for the world?

Handwashing with soap is regarded as one of the most cost-effective interventions to improve public health. This is mainly because the simple action of washing hands with soap can interrupt the transmission of the pathogens that cause diarrhoea and pneumonia, the two biggest killers of children under-five. The latest estimates of the global causes of child mortality attribute 0.751 million (uncertainty range 0.538 - 1.031 million) deaths among children aged 1 to 59 months a year to diarrhoea and 1.071 million (uncertainty range 0.977 - 1.176 million) to pneumonia. Reviews of epidemiological studies suggest that universal practice of handwashing with soap could reduce the risk of severe diarrhoea by 48% and the risk of any diarrhoea by 47%. A further review, updated by the authors to include findings from a subsequent study concludes that handwashing with soap could reduce the risk of lower respiratory tract infections like pneumonia by up to 23%. [authors abstract]