Background: There is limited information on differences in the dynamics of influenza transmission during time periods when schools are open compared with periods when they are closed.
Methods: Data on school openings, influenza surveillance, and absolute humidity were incorporated into a regression model to estimate the increase in the reproductive number for the 2009 A(H1N1) influenza pandemic associated with the opening of school in 10 US states.
Results: The estimate for the average increase in the reproductive number for the 2009 A(H1N1) influenza pandemic associated with the beginning of the school year was 19.5% (95% credible interval = 10%–29%).
Conclusions: Whether schools are open or closed can have a major impact on community transmission dynamics of influenza.
From the aDepartment of Epidemiology, Center for Communicable Disease Dynamics, Harvard School of Public Health, Boston, MA; bDepartment of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA; and cDepartment of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, NY.
Supported by Award Number U54GM088558 from the National Institute Of General Medical Sciences (K.H., M.L., J.S.., E.G.), by the US National Institutes of Health K01 award 1K01AI101010-01 (E.G.), and by NIEHS Center Grant ES009089 and the RAPIDD program of the Science and Technology Directorate, US Department of Homeland Security (J.S). The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institute of General Medical Sciences or the National Institutes of Health.
Marc Lipsitch is on the Editorial Board for Epidemiology. Marc Lipsitch discloses consulting income from the Avian/Pandemic Flu Registry (Outcome Sciences, funded in part by Roche) and from Pfizer/Wyeth and from Novartis Vaccines and Diagnostics. The other authors declare no competing interests.
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Correspondence: Edward Goldstein, 677 Huntington Ave, Kresge Room 506, Boston, MA 02115. E-mail: firstname.lastname@example.org.