A Novel Active Respiratory Syncytial Virus Surveillance System in the United States Variability in the Local and Regional Incidence of Infection

Background: To characterize the onset, peak, and duration of the RSV season in major metropolitan areas in the United States as determined from laboratory test data collected by a novel RSV surveillance program (RSV Alert), including regional and national trends. Methods: We prospectively analyzed results of more than 600,000 tests collected weekly during 3 seasons (2004/2005-2006/2007) by the RSV Alert program. More than 200 institutions participated in the first 2 seasons of the program, and more than 600 sites in the third. Data were analyzed for trends in season onset, offset, and duration at the local, regional, and national levels. Results: Considerable variability in season onset and duration was noted between metropolitan areas located geographically within the same region. Seasonal outbreaks of RSV consistently peaked first, concluded earliest, and were of longest duration in the Southern region. The onset of the RSV season occurred latest and peaked last in the Midwest region each season. Conclusions: The variable nature Of Outbreaks observed between metropolitan areas located geographically within the same regions of the country is highlighted through data collected for 3 consecutive seasons. The RSV Alert program is a valuable reporting system that provides real-time surveillance data at a city/local level nationwide and has potential to aid clinicians in decisions regarding RSV management.