New Vanderbilt-led research published in the Feb. 14 issue of the New England Journal of Medicine has identified the relatively unknown human metapneumovirus (MPV) as the second most common cause of severe bronchiolitis in young children.
Senior author John Williams , M.D., associate professor of Pediatric Infectious Diseases and a well-known expert in MPV research, said it is gratifying to offer a clearer picture of how this virus impacts children.
"We found MPV is as important a cause of respiratory illness as influenza, and caused more illness than the three common types of parainfluenza virus combined. In fact, in young children, the burden of MPV was second only to RSV (respiratory syncytial virus) as a cause of bronchiolitis," Williams said.
The prospective research spanned six years, from 2003 to 2009, and involved samples taken from more than 10,000 children under age 5. The children were hospitalized, treated in an emergency department, or seen in an outpatient clinic with a lower respiratory infection (bronchiolitis).
Lead author Kathryn Edwards, M.D., the Sarah H. Sell and Cornelius Vanderbilt Chair in Pediatrics and director of the Vanderbilt Vaccine Research Program, led the clinical portion of the study while Williams' laboratory tested the samples for their viral content.
Three New Vaccine Surveillance Network (NVSN) sites participated: Rochester, N.Y., Cincinnati and Nashville, making this the largest prospective trial to date to investigate the burden of MPV.
Researchers found MPV tends to affect more children over age 1 than RSV, and while both viral infections strike in late winter or spring, MPV has a seasonal peak that lags behind the typical peak for RSV by about a month. The authors said physicians commonly see patients with this virus, but know little about it.