Viral pneumonias. Epidemic respiratory viruses.

Influenza, respiratory syncytial, and parainfluenza viruses usually cause mild, self-limited illness in adults. However, elderly and immunocompromised persons are at increased risk for development of severe pneumonia. Clinical and radiographic features of epidemic viral pneumonias are often nonspecific. Newer and faster methods of viral culture and viral antigen detection have improved the capability for definitive diagnosis in recent years. Preventive measures for influenza virus pneumonia center on limiting exposure of high-risk patients to active cases of influenza, administering annual vaccinations, and providing chemoprophylaxis. Prophylaxis against RSV is effective in preventing complications. No effective vaccines have been developed against RSV or parainfluenza. Therapy for viral pneumonia is primarily supportive. Amantadine may be beneficial for influenza virus pneumonia, and ribavirin may be useful for RSV and parainfluenza virus disease. However, further definitive studies are necessary to determine their roles in these viral pneumonias.