Using census data and data on pediatric acute respiratory illness from the National Hospital and Ambulatory Medical Care Survey, Bourgeois and colleagues were able to extrapolate their data nationally and determine population-based rates of RSV and flu illnesses. They estimate that 21.5 ED visits per 1,000 children were attributable to RSV, as compared with 10.2 per 1,000 for seasonal flu. Children under age 2 with RSV had the most visits - 64.4 per 1,000. Estimated hospitalization rates were 8.5 per 1000 for RSV, versus 1.4 per 1000 for flu. Nationally, caregivers missed an estimated 716,404 workdays each year for RSV and 246,965 for flu.

Although the study only looked at children age 7 and younger, the researchers believe their findings are relevant to older age groups, since young children drive transmission of viral infections, the researchers say. Recent hospitalization and mortality data indicate that, like flu, RSV disproportionately affects elderly persons.

While H1N1 may change the equation this year - there are indications that it's causing a greater burden of illness than seasonal flu - we shouldn't relax our public-health vigilance once that epidemic starts to wane, says Bourgeois. "Many of the prevention measures people are following for H1N1 - such as frequent handwashing, using alcohol-based hand-sanitizers, and staying home when they're sick - should apply every winter, to every viral season," she says.

SOURCE Children's Hospital Boston