Background: Recent studies indicate that influenza can be clinically important in otherwise healthy children. However, the interpretation of many studies is limited because of lack of laboratory confirmation of influenza-like illnesses. Therefore it is difficult to conclude whether the socioeconomic impact of influenza justifies vaccinating all children regardless of age or underlying chronic disorders.
Methods: We prospectively collected data from 3771 children younger than 14 years of age presenting to emergency departments or primary care pediatricians with symptoms of respiratory tract infection during the influenza season of 2001 to 2002. Influenza infections were verified by virus culture or polymerase chain reaction. We additionally randomized 303 children age 6 months to 5 years to receive either influenza vaccine (n = 202) or no vaccination (n = 101) before the influenza season. The socioeconomic impact of influenza was assessed for both the participating children and their household contacts.
Results: Influenza was documented in 352 (9.3%) of the 3771 children. Compared with influenza-negative children, children with influenza had longer durations of fever and absenteeism from day care or school (P < 0.0001). Further the numbers of medical visits, missed work or school days and the need for help at home to care for the sick children were higher among the household contacts of influenza-positive children (P < 0.0001). Influenza vaccination reduced significantly the direct and indirect influenza-related costs in healthy children and their unvaccinated family members.
Conclusions: The findings of this study support a wider use of influenza vaccine in healthy children of all ages to reduce the socioeconomic burden of influenza on the community.