Update: respiratory syncytial virus activity--United States, 1996-97 season.

Respiratory syncytial virus (RSV), a common cause of winter outbreaks of acute respiratory disease, results in an estimated 90,000 hospitalizations and 4500 deaths each year from lower respiratory tract disease in both infants and young children in the United States. Outbreaks occur annually throughout the country. RSV activity in the United States is monitored by the National Respiratory and Enteric Virus Surveillance System (NREVSS), a voluntary, laboratory-based system. This report summarizes trends in RSV from the NREVSS from July 1, 1990, through June 28, 1996, and presents provisional surveillance results for June 29-November 29, 1996. These data indicate onset of widespread RSV activity for the 1996-97 season.