Burden of influenza in children in the community

Background. Influenza vaccination of healthy children is encouraged because children are frequently hospitalized for influenza-attributable illnesses. However, most children with influenza are treated as outpatients, and scarce data are available on the burden of influenza in these children. Methods. We performed a prospective study of respiratory infections in preenrolled cohorts of children less than or equal to13 years old during 2 consecutive respiratory seasons (2231 child-seasons of follow-up). At any sign of respiratory infection, we examined the children and obtained a nasal swab for the detection of influenza. The parents filled out daily symptom diaries. Of all the enrollees, 94% remained active participants in the study. Results. The average annual rate of influenza was highest (179 cases/1000 children) among children <3 years old. Acute otitis media developed as a complication of influenza in 39.7% of children <3 years old. For every 100 influenza-infected children <3 years old, there were 195 days of parental work loss (mean duration, 3.2 days). Conclusions. Influenza causes a substantial burden of illness on outpatient children and their families. Vaccination of children <3 years old might be beneficial for reducing the direct and indirect costs of influenza in children.