Respiratory viruses. Current status and future prospects.

The application of tissue culture technology has revealed several new groups of viruses, comprising scores of different serotypes, as important causes of upper and lower respiratory tract disease in man. Other agents as yet unrecognized undoubtedly exist. Present epidemiologic data, although still incomplete, point up the unique importance of certain of these viruses in respiratory diseases. The particular type and severity of respiratory syndrome produced by a virus is determined by the immune status of the host, by the presence of complicating disease and by characteristics intrinsic in the infecting agent itself. Respiratory virus control might be particularly beneficial in certain groups, particularly persons with allergic sensitivity and chronic pulmonary disease.For control of viral respiratory disease, active immunization would provide significant protection but highly polyvalent vaccines might be necessary. Adjuvants could be helpful in this regard. Certain vaccines formerly in use were produced from strains of viruses which have recently been shown to be oncogenic in animals. In addition, hybridization of viruses can occur, resulting in the incorporation of the oncogenic potential of one agent into the genetic constitution of another. The significance of these biologic phenomena to vaccination programs has yet to be defined.Passive immunization would provide short-lived protection and would find application only in uniquely susceptible populations or at times of augmented risk. Active immunization of pregnant women, however, could provide increased breadth and duration to the transplacental passive immunity in the newborn.Interferon-inducing agents could potentially provide broad spectrum antiviral protection, but the extent and duration of their effectiveness are unknowns. Certain chemical agents have been shown to have prophylactic and therapeutic effects against a limited number of clinically severe viral diseases. Finally, limited data suggest that climatic control in places of public gathering might be worth evaluating as a means of controlling the spread of viral respiratory infections.