Pharmaceutical interventions, particularly vaccination, have been the principal public health method of preventing and controlling seasonal influenza. Other less invasive non-pharmaceutical interventions include the use of face masks and hand hygiene. In Asia, masks are used extensively, especially in Japan, but with only circumstantial evidence of efficacy. Although there are numerous studies that support hand hygiene as an effective measure for decreasing transmission of enteric infections, there are fewer data assessing the effect of hand hygiene on respiratory illnesses. Therefore it is proposed that a study be conducted on the use of face masks with and without the use of hand hygiene in comparison to no intervention in residence housing units of the University of Michigan. The interventions will be carried out during a period of influenza transmission that is defined by surveillance conducted at the University Health Service. Data will be collected on use of the interventions and the occurrence of influenza and other illnesses. When illness occurs meeting a case definition, specimens for viral isolation will be collected in all intervention settings. Face masks could theoretically lead to a large reduction in transmission frequency of influenza, especially if most transmission occurs by the airborne (large or small droplet) route. Even a modest reduction could have a major effect during an influenza pandemic.