Closing schools for less than two weeks during a flu pandemic may increase infection rates and prolong an epidemic. The value of school closures has been debated as a possible strategy to stem or slow the current H1N1 influenza pandemic. Indeed, hundreds of schools across the country have been closed at different periods during 2009 for fear the virus would spread more quickly if they stayed open. The study was based on an agent-based computer simulation model that included more than 500,000 households and nearly 300 schools. Entire school system closures were not more effective than individual school closures. Any type of school closure may need to be maintained throughout most of the epidemic (ie, at least 8 weeks) to have any significant effect on the overall serologic attack rate. In fact, relatively short school closures (ie, 2 weeks or less) may actually slightly increase the overall attack rate by returning susceptible students back into schools in the middle of the epidemic. Varying the illness threshold at which school closures are triggered did not seem to have substantial impact on the effectiveness of school closures, suggesting that short delays in closing schools should not cause concern. The authors conclude that school closures alone may not be able to quell an epidemic but, when maintained for at least 8 weeks, could delay the epidemic peak for up to a week, providing additional time to implement vaccination.

Mothers who do not breastfeed their infants appeared to be at increased risk of vascular changes associated with future cardiovascular disease, in a cross-sectional analysis of 297 women (45-58 y) free of clinical cardiovascular disease who reported at least one live birth on enrollment. After adjusting for measures of socioeconomic status and lifestyle and family history variables, mothers who had not breastfed remained more likely to have aortic calcification (odds ratio [OR] 3.85) and coronary artery calcification (OR 2.78).