Brief report: respiratory syncytial virus activity--United States, 2005-2006.

Respiratory syncytial virus (RSV) is a major cause of lower respiratory tract infections (LRTIs) (e.g., bronchiolitis and pneumonia) among young children in the United States. RSV also causes severe respiratory disease and a substantial number of deaths among older adults and persons with compromised respiratory, cardiac, or immune systems. RSV is transmitted person to person through close contact or inhalation of large droplets from a sneeze or cough; infection also can occur through contact with fomites (i.e., contaminated surfaces or objects). In temperate climates, peak RSV activity typically occurs during the winter. This report presents preliminary data on RSV activity reported to the National Respiratory and Enteric Virus Surveillance System (NREVSS) for the weeks ending July 8-November 18, 2006, indicating the onset of the 2006-2007 RSV season, and summarizes RSV trends during July 2005-June 2006. Health-care providers should consider RSV in the differential diagnosis for persons of all ages with LRTIs and implement appropriate isolation precautions to prevent nosocomial transmission from RSV-infected patients. Immune prophylaxis should be considered for certain infants and young children at high risk for complications from RSV infection (e.g., certain premature infants or infants and children with chronic lung and heart disease).