An estimated 2 million children under age 5 years require medical attention for respiratory syncytial virus each year, a “much larger burden than previously recognized,” according to an analysis of surveillance data on more than 5,000 children.
Recent data from the Centers for Disease Control and Prevention's New Vaccine Surveillance Network show that respiratory syncytial virus (RSV) infection prompts 1 of every 13 visits to primary care physicians in the United States, as well as 1 of every 38 emergency department visits and 1 of every 334 hospitalizations, in this age group. Hospitalization rates for children who prove to have RSV are three times higher than those for children whose illness is caused by influenza or parainfluenza, even in populations where the rate of flu vaccination is quite low.
The virus's major burden on health care resources occurs in healthy children who are not considered at risk and many of whom are well beyond infancy, said Dr. Caroline Breese Hall, professor of pediatrics and medicine at the University of Rochester (N.Y.), and her associates.
The heavy outpatient burden in particular “is probably not fully recognized by health care providers and by public health officials, since only 3% of outpatients with confirmed RSV infection received the specific diagnosis of RSV infection; bronchiolitis was diagnosed in 20% of such children,” and other missed diagnoses included simple upper respiratory tract infection (32%), asthma (13%), and pneumonia (8%).
The investigators analyzed surveillance data gathered from November through April in each year from 2000 to 2004 on acute respiratory infections among children under age 5 years in three geographically diverse U.S. populations. The children enrolled in the study were hospitalized, treated in outpatient emergency departments, or seen in pediatricians' offices.
This study involved 5,067 children, of whom 919 (18%) were found by culture and/or reverse transcriptase polymerase chain reaction to have RSV infection. RSV was associated with 20% of hospitalizations, 18% of outpatient visits to the emergency department, and 15% of office visits for acute respiratory infections in this population. (New Engl. J. Med. 2009;360:588–98).
“If we extrapolate from our population-based data to the entire U.S. population, an estimated 2.1 million children under 5 years of age with RSV infection would require medical attention each year.” Nearly three-fourths of the affected children would be treated in private practices, 3% would be hospitalized, and the remaining 24% would be treated in emergency departments.
Fully 78% of RSV-infected children would be older than 1 year. Most would have no coexisting medical conditions or traits that would identify them as being at risk, the investigators said.
Dr. Hall reports receiving grant support and consulting fees from MedImmune Inc.