Update: respiratory syncytial virus activity--United States, 1993.

Respiratory syncytial virus (RSV), a common cause of community-wide outbreaks of acute respiratory disease, is associated with an estimated 90,000 hospitalizations and 4500 deaths from lower respiratory tract disease in both infants and young children in the United States. Outbreaks usually occur from late fall or early winter through spring. Since 1989, RSV activity in the United States has been monitored by the National Respiratory and Enteric Virus Surveillance System (NREVSS), a voluntary, laboratory-based system. This report summarizes surveillance results from NREVSS for RSV detections from July 1, 1993, through December 11, 1993, and assesses trends in RSV from July 1, 1990, through December 11, 1993.