Studies of acute respiratory illnesses in families and their communities have been carried out for most of this century. The initial studies established the importance of these illnesses in terms of their frequency and severity. Age-specific illness rates and principles concerning disease transmission were documented in the period before identification of the etiologic agents. Since that time, the knowledge base has been expanded dramatically. Of all the viruses, rhinoviruses cause more illness of any severity than any other in all age groups. As a result, rates of rhinovirus-specific illnesses resemble those of all-cause respiratory illnesses. The greatest advantage of community-based studies is their ability to study transmission. Since control of infection for most of the agents has been difficult to achieve by conventional means, interruption of transmission should be examined as a possible alternative (97).