School closures can alter transmission dynamics of pandemic influenza

January 01, 0001

School closures can alter transmission dynamics of pandemic influenza

Mexico's local and national authorities initiated an intense public health response during the early stages of the 2009 A/H1N1 pandemic. In this study the researchers from the USA and Mexico analyzed the epidemiological patterns of the pandemic during April-December 2009 in Mexico and evaluated the impact of nonmedical interventions, school cycles, and demographic factors on influenza transmission. They used influenza surveillance data compiled by the Mexican Institute for Social Security, representing 40% of the population, to study patterns in influenza-like illness (ILIs) hospitalizations, deaths, and case-fatality rate by pandemic wave and geographical region.

They estimated that the 18-day period of mandatory school closures and other social distancing measures implemented in the greater Mexico City area was associated with a 29%-37% reduction in influenza transmission in spring 2009. In addition, an increase in R was observed in late May and early June in the southeast states, after mandatory school suspension resumed and before summer vacation started. State- specific fall pandemic waves began 2-5 weeks after school reopened for the fall term, coinciding with an age shift in influenza cases.

The researchers concluded: "We documented three spatially heterogeneous waves of the 2009 A/H1N1 pandemic virus in Mexico, which were characterized by a relatively young age distribution of cases. Our study highlights the importance of school cycles on the transmission dynamics of this pandemic influenza strain and suggests that school closure and other mitigation measures could be useful to mitigate future influenza pandemics."

This does appear to be an important step in reducing spread of influenza, but not every season nor strain.

For the full abstract, click here.

PLoS Med 8(5):e1000436, 24 May 2011 © 2011 Chowell et al
Characterizing the Epidemiology of the 2009 Influenza A/H1N1 Pandemic in Mexico. Gerardo Chowell, Santiago Echevarría-Zuno, Cécile Viboud et al. Correspondence to Gerardo Chowell: [email protected]

Category: GH. Global Health. Keywords: epidemiology, influenza, epidemic, Mexico, analysis of influenza surveillance data, journal watch.
Synopsis edited by Dr Stephen Wilkinson, Melbourne, Australia. Posted on Global Family Doctor 24 June 2011

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