Underestimation of Influenza Viral Infection in Childhood Asthma Exacerbations

It has long been recognized that viral infections are associated with asthma exacerbations in childhood. A respiratory virus is usually identified in children with asthma exacerbations and rhinovirus, respiratory syncytial virus (RSV), and bocavirus are the most commonly detected. The relative importance of influenza viruses in children with asthma is widely debated. Some studies have concluded that influenza vaccination did not result in a significant reduction of asthma exacerbations,(1,2) but other studies have shown that influenza-attributable health care use is frequent in children with asthma.(3-5) In earlier studies, we have found influenza viruses in only 3% to 4% of children hospitalized for acute asthma.(6-7) For this reason, we have compared inpatients and outpatients with asthma exacerbations to determine the burden of influenza virus.