Effectiveness of a school district closure for pandemic influenza A (H1N1) on acute respiratory illnesses in the community: A natural experiment

Abstract

Background. Following detection of pandemic influenza A H1N1 (pH1N1) in Dallas/Fort Worth, Texas, a school district (intervention community, [IC]) closed all public schools for 8 days to reduce transmission. Nearby school districts (control community [CC]) mostly remained open.Methods. We collected household data to measure self-reported acute respiratory illness (ARI), before, during, and after school closures. We also collected influenza-related visits to emergency departments (EDflu).Results. In both communities, self-reported ARIs and EDflu visits increased from before to during the school closure, but the increase in ARI rates was 45% lower in the IC (0.6% before to 1.2% during) than in the CC (0.4% before to 1.5% during) (RRR During/Before = 0.55, P