Recommendations and Reports 82. Wang L, Chu C, Yang G, et al. Transmission characteristics of different 94. Blyth CC, Foo H, van Hal SJ, et al; World Youth Day 2008 Influenza students during a school outbreak of (H1N1) pdm09 influenza in China, Study Group. Influenza outbreaks during World Youth Day 2008 mass 2009. Sci Rep 2014;4:5982. gathering. Emerg Infect Dis 2010;16:809–15. https://doi.org/10.3201/ 83. Glass RI, Brann EA, Slade JD, et al. Community-wide surveillance of eid1605.091136 influenza after outbreaks due to H3N2 (A/Victoria/75 and A/Texas/77) 95. Shi P, Keskinocak P, Swann JL, Lee BY. The impact of mass gatherings and H1N1 (A/USSR/77) influenza viruses, Mercer County, New and holiday traveling on the course of an influenza pandemic: a Jersey, 1978. J Infect Dis 1978;138:703–6. https://doi.org/10.1093/ computational model. BMC Public Health 2010;10:778. https://doi. infdis/138.5.703 84. Nichol KL, D’Heilly S, Ehlinger EP. Influenza vaccination among org/10.1186/1471-2458-10-778 college and university students: impact on influenzalike illness, health 96. Benkouiten S, Charrel R, Belhouchat K, et al. Circulation of respiratory care use, and impaired school performance. Arch Pediatr Adolesc Med viruses among pilgrims during the 2012 Hajj pilgrimage. Clin Infect 2008;162:1113–8. https://doi.org/10.1001/archpedi.162.12.1113 Dis 2013;57:992–1000. https://doi.org/10.1093/cid/cit446 85. Wong KK, Shi J, Gao H, et al. Why is school closed today? Unplanned 97. Memish ZA, Assiri A, Turkestani A, et al. Mass gathering and K–12 school closures in the United States, 2011–2013. PLoS One globalization of respiratory pathogens during the 2013 Hajj. Clin 2014;9:e113755. https://doi.org/10.1371/journal.pone.0113755 Microbiol Infect 2015;21:571.e1–8. https://doi.org/10.1016/j. 86. Russell ES, Zheteyeva Y, Gao H, et al. Reactive school closure during cmi.2015.02.008 increased influenza-like illness (ILI) activity in Western Kentucky, 2013: 98. Bischoff WE, Swett K, Leng I, Peters TR. Exposure to influenza virus a field evaluation of effect on ILI incidence and economic and social aerosols during routine patient care. J Infect Dis 2013;207:1037–46. consequences for families. Open Forum Infect Dis 2016;3:ofw113. 87. Davis BM, Markel H, Navarro A, Wells E, Monto AS, Aiello AE. The https://doi.org/10.1093/infdis/jis773 effect of reactive school closure on community influenza-like illness 99. Weber TP, Stilianakis NI. Inactivation of influenza A viruses in the counts in the state of Michigan during the 2009 H1N1 pandemic. Clin environment and modes of transmission: a critical review. J Infect Infect Dis 2015;60:e90–7. https://doi.org/10.1093/cid/civ182 2008;57:361–73. https://doi.org/10.1016/j.jinf.2008.08.013 88. Gatwood J, Meltzer MI, Messonnier M, Ortega-Sanchez IR, 100. Langmuir AD, Pizzi M, Trotter WY, Dunn FL. [Asian influenza Balkrishnan R, Prosser LA. Seasonal influenza vaccination of healthy surveillance]. Public Health Rep 1958;73:114–20. https://doi. working-age adults: a review of economic evaluations. Drugs org/10.2307/4590057 2012;72:35–48. https://doi.org/10.2165/11597310-000000000-00000 101. Lim HC, Cutter J, Lim WK, Ee A, Wong YC, Tay BK. The influenza A 89. Balkhy HH, Memish ZA, Bafaqeer S, Almuneef MA. Influenza (H1N1-2009) experience at the inaugural Asian Youth Games Singapore a common viral infection among Hajj pilgrims: time for routine 2009: mass gathering during a developing pandemic. Br J Sports Med surveillance and vaccination. J Travel Med 2004;11:82–6. https://doi. org/10.2310/7060.2004.17027 2010;44:528–32. https://doi.org/10.1136/bjsm.2009.069831 90. Abubakar I, Gautret P, Brunette GW, et al. Global perspectives for 102. Kelso JK, Milne GJ, Kelly H. Simulation suggests that rapid activation prevention of infectious diseases associated with mass gatherings. of social distancing can arrest epidemic development due to a novel Lancet Infect Dis 2012;12:66–74. https://doi.org/10.1016/ strain of influenza. BMC Public Health 2009;9:117. https://doi. S1473-3099(11)70246-8 org/10.1186/1471-2458-9-117 91. Gutiérrez I, Litzroth A, Hammadi S, et al. Community transmission of 103. Sadique MZ, Edmunds WJ, Smith RD, et al. Precautionary behavior influenza A (H1N1)v virus at a rock festival in Belgium, 2-5 July 2009. in response to perceived threat of pandemic influenza. Emerg Infect Euro Surveill 2009;14:19294. Dis 2007;13:1307–13. https://doi.org/10.3201/eid1309.070372 92. Rashid H, Haworth E, Shafi S, Memish ZA, Booy R. Pandemic influenza: 104. Berkman BE. Mitigating pandemic influenza: the ethics of implementing mass gatherings and mass infection. Lancet Infect Dis 2008;8:526–7. a school closure policy. J Public Health Manag Pract 2008;14:372–8. https://doi.org/10.1016/S1473-3099(08)70186-5 93. Rainey JJ, Phelps T, Shi J. Mass gatherings and respiratory disease https://doi.org/10.1097/01.PHH.0000324566.72533.0b outbreaks in the United States—should we be worried? Results from a systematic literature review and analysis of the National Outbreak Reporting System. PLoS One 2016;11:e0160378. https://doi. org/10.1371/journal.pone.0160378 24 MMWR / April 21, 2017 / Vol. 66 / No. 1 US Department of Health and Human Services/Centers for Disease Control and Prevention