Transmission of the Common Cold to Volunteers Under Controlled Conditions

The common cold is one of the most frequent and universal infections of man. Nevertheless, little is known regarding its specific etiology, and the diagnosis must be a clinical one. Until the infectious agent can be propagated, characterized by microbiologic and pathologic methods and consistently transmitted to experimental animals or in tissue cultures, transmission to humans appears to be the best method for study. In this manner, information can be obtained about the nature of the infection, factors that influence the susceptibility or resistance of the human host, and conditions that favor spread of the illness. During the past five years we have made observations upon more than 1000 volunteers who were challenged with infectious nasal secretions obtained from persons with a common cold or with a blank solution used as a control. The clinical findings were re- corded daily. Examination of the nose and throat was of no value