Handwashing with soap is the best way to control flu and respiratory infections

People are more likely to wash their hands when they have been shamed into it, according to a study by the London School of Hygiene & Tropical Medicine.

The study, published in the American Journal of Public Health, looked at responses to electronic hygiene messages displayed in UK service station toilets.

A million people die every year from diarrhoeal disease and respiratory infection. Handwashing with soap is the cheapest and best way of controlling these diseases. It also prevents the spread of flu, and hospital-acquired infections such as Clostridium difficile. However, "it's difficult to know what kind of message is most effective at changing this everyday behaviour, so it's important to experimentally test what works best in a real setting. That way you can save money and make sure your programme will be effective prior to rolling out any public health campaign at great expense" says Robert Aunger, leader of the study.

A quarter of a million people were counted using the toilets and their use of soap was monitored by on-line sensors. Only 32% of men washed their hands with soap whilst women were twice as good, with 64% washing their hands.

A variety of messages, ranging from 'Water doesn't kill germs, soap does' to 'Don't be a dirty soap dodger', were flashed onto LED screens at the entrance of the toilets and the effects of the messages on behaviour were measured. 'Is the person next to you washing with soap?' was best overall, showing how people respond to whether they thought others were watching. There were intriguing differences in behaviour by gender, with women responding to reminders, while men tended to react best to messages that invoked disgust, for example 'soap it off or eat it later'.

Gaby Judah, who ran the study said: "Our findings are particularly important on Global Handwashing Day, when many agencies concerned with improving health worldwide by encouraging people to wash their hands with soap will be looking to use best practice." Global Handwashing Day is on 15th October.