Acute respiratory tract infections (ARIs) caused by viruses are not easily treated, so public health measures to prevent transmission are important. Most ARIs cause only mild, self-limiting illnesses. Nevertheless, they account for considerable loss of time from school and work, disrupting education and affecting the economy. The role of hygiene, especially handwashing in reducing the risk of infection, was established in research studies in the 1970s, but few members of the public or health professionals appear to recognise the importance of hand hygiene. The emergence of new, more serious ARIs may renew interest in hygiene, particularly hand hygiene, as an important preventive measure.