A strategy called “social distancing,” which included mandatory closures of schools for 18-day periods and other measures, was associated with a substantial reduction in influenza transmission rates in Mexico during the 2009 influenza A(H1N1) pandemic, reported scientists from the Fogarty International Center at the National Institutes of Health (Chowell G et al. PLoS Med. 2011;8:e1000436).
Using mathematical modeling to analyze influenza surveillance data compiled by the Mexican Institute for Social Security, the researchers identified 3 waves of infection that occurred in 2009: the first in April-May, the second in June-July, and the third in August-December. In late April 2009, the Ministry of Health ordered schools to close and subsequently implemented other social distancing measures in the Mexico City area, including closing movie theaters and restaurants and cancelling large public gatherings.