Effect of school closure on the incidence of influenza among school-age children in Arizona

Objective. We assessed the impact of school closures as a viable intervention in the event of an influenza pandemic. Methods. We evaluated the effect of scheduled, two-week winter break school closures during the 2004-2008 school years on the occurrence of influenza among children aged 5-17 years in Arizona. Results. We found a consistent pattern of benefit to school-age children during winter school closures when non-school-age children and adults experienced significant increases in influenza incidence, an increase not seen among school-age children. Quantitative analysis showed that school closures may prevent or delay as much as 42% of potential influenza cases among school-age children. In addition, the ratio of illness in school-age children as compared with adults and non-school-age children decreased significantly from before to during the same school closure periods. Conclusion. This analysis provides evidence to suggest that school-age children may experience a slowing of influenza transmission during winter school closures compared with those not of school age. Federal, state, and local policy makers may consider these findings in their pandemic influenza and public health emergency preparedness planning efforts.