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Trends and Surveillance

Respiratory syncytial virus (RSV) is the most common cause of lower respiratory tract infections among young children in the United States and worldwide. Most infants are infected before 1 year of age, and virtually everyone gets an RSV infection by 2 years of age.

Each year, on average, in the United States, RSV leads to—

  • 57,527 hospitalizations among children younger than 5 years old
  • 100,000 to 126,000 hospitalizations among children younger than 1 year old
  • 2.1 million outpatient visits among children younger than 5 years old
  • 177,000 hospitalizations and 14,000 deaths among adults older than 65 years

In the United States and other areas with similar climates, RSV infections occur primarily during fall, winter, and spring.

RSV Seasonal Trends

Chart: Duration of RSV Season, by U.S. Department of Health and Human Services Region and Florida, July 2013 - June 2014 (listed by region number, or state, and headquarter city in order from earliest to latest RSV season start date): Florida onset: July 2013; offset: late February 2014. Region 6 (Dallas) onset: mid-October 2013; offset: late March 2014. Region 4 (Atlanta) onset: early November 2013; offset: late February 2014. Region 2 (New York) onset: mid-November 2013; offset: late January 2014. Region 3 (Philadelphia) onset: mid-November 2013; offset: early February 2014. Region 5 (Chicago) onset: early December 2013; offset: mid-April 2014. Region 7 (Kansas City) onset: early December 2013; offset: late April 2014. Region 1 (Boston) onset: mid-December 2013; offset: mid-February 2014. Region 10 (San Francisco) onset: mid-December 2013; offset: mid-April 2014. Region 10 (Seattle) onset: late December 2013; offset: mid-April 2014. Region 8 (Denver) onset: mid-January 2013; offset: mid-April 2014.

CDC analyzes data on RSV activity at the national, regional, and state levels, collected by a surveillance system called the National Respiratory and Enteric Virus Surveillance System (NREVSS).

For 2013 to 2014, the RSV season onset ranged from late October to late January, and season offset ranged from late January to early April in all 10 U.S. Department of Health and Human Services (HHS) regions, except Florida. Florida has an earlier RSV season onset and longer duration than the rest of the country (see figure).

Seasonal patterns remained consistent with previous years.

Surveillance Systems

Information on cases and outbreaks of RSV infection is collected in the United States using the National Respiratory and Enteric Virus Surveillance System (NREVSS). This is a voluntary, laboratory-based surveillance system that was established in 1989 to monitor trends in several viruses, including RSV. NREVSS tracks the number of RSV tests that are done by participating laboratories and the proportion that are positive, by specimen type, location, and when they were collected. Serotyping, demographic data, and clinical data are not reported. Data from NREVSS provides information to public health officials and healthcare providers about the presence of RSV in their communities.

References

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