Respiratory Syncytial Virus Varies Widely In Season Onsets And Offsets

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Main Category: Infectious Diseases / Bacteria / Viruses
Also Included In: Respiratory / Asthma;  Public Health
Article Date: 07 Oct 2007 - 0:00 PDT

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Investigators are reporting dramatic variability in seasonal onset and offset of respiratory syncytial virus (RSV) outside of presumptive outbreak periods and vicinities.

The findings, based on three-year data from a novel RSV surveillance program known as RSV AlertTM, were released at the 45th Annual Meeting of the Infectious Diseases Society of America (IDSA).

"Our results undermine the popular notion that RSV is predictable in both time period and geography," Jessie R. Groothuis, MD, Vice-President and Head of Medical and Scientific Affairs in Infectious Disease at MedImmune, Inc. in Gaithersburg, Maryland, pointed out.

Importantly, the findings can help practitioners more accurately plan for such outbreaks, she added. "Presently, there is no uniformity in RSV testing," she said. "What's more, local, up-to-date data are not consistently available, specifically regarding the onset and offset of the RSV season. Our RSV surveillance program provides a more accurate retrieval mechanism for RSV detection and should help practitioners make time-sensitive decisions regarding the duration of RSV prevention and management."

The RSV AlertTM program was established to evaluate the variability of the RSV season temporally and geographically in the U.S. by tracking significant (greater than 10% positive levels) activity at the community level with timely reporting, Dr. Groothuis explained.

The program incorporates real-time, weekly reports of RSV tests performed in a majority of Metropolitan Statistical Areas (MSAs) in the U.S.

The present analysis included laboratory RSV testing results collected from September 2004 through May 2007. Sites were recruited according to geographic location and reporting capabilities.

Overall, in the 2006/07 season, approximately 700 sites provided data nationwide, including 39 pediatric centers, representing about 74% of the US population.

During the three-year study period, 185 hospital laboratories showed greater than 10% positivity in either September or October in all regions defined by the Centers for Disease Control (CDC).

The analysis also documented variability in percent positivity for smaller vicinities within a region for the same time period. For example, areas in the Midwest had earlier RSV onsets (September, October) in 2006-2007, while others described later onsets. RSV positivity also tended to vary in the same region from year to year.

"Until now, hospital- and clinic-based practitioners gauge when RSV season is likely to start and end using a CDC databank which provides information on regional but not local levels," Dr. Groothuis said. "The RSV AlertTM program uses highly localized data to provide seasonal detection information which can help practitioners optimize planning for outbreaks in terms of prevention and management."

Finally, she added that the CDC is "so impressed by the results" that it has decided to incorporate data from RSV AlertTM into its own RSV surveillance program on an ongoing basis.

RSV AlertTM is administered and managed by Surveillance Data, Inc. (SDI) in Plymouth Meeting, Pennsylvania, which provides disease surveillance information in several countries worldwide.

Infectious Diseases Society of America

By Jill Stein
Jill Stein is a Paris-based medical writer
Jillstein03 at cs.com
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