Nosocomial viral respiratory infections: perennial weeds on pediatric wards.

The frequency and importance of nosocomial infections of the respiratory tract in pediatrics have generally been underestimated. In part this has resulted from the emphasis on bacterial infections which occur primarily in select at-risk populations. Most respiratory infections in pediatric patients, hospital- and community-acquired, are viral and all patients are potentially susceptible The epidemiologic patterns of these viral respiratory agents on the ward mirror those seen in the community in terms of frequency, season, age affected and severity of illness. Hence, the most frequent nosocomial agents are the viruses that occur in outbreaks or epidemics and cause respiratory illness, epidemic respiratory viruses--respiratory syncytial virus, which causes the greatest morbidity and mortality; influenza, and the parainfluenza viruses. Their import, as exemplified by respiratory syncytial virus, results from (1) the severity of disease produced in young children, which is magnified in those hospitalized with certain underlying conditions; (2) the abundant and prolonged viral shedding, allowing easy spread; (3) the potential susceptibility of all patients and staff, since infections recur throughout life; and (4) the difficulty in controlling nosocomial spread.