Short-term school closings are not an effective way to block the spread of influenza viruses, and may even be counterproductive, Pennsylvania researchers have found. To be fully effective, the closures must last at least eight weeks, they reported in the Journal of Public Health Management and Practice.
School closures were common last spring during the first wave of pandemic H1N1 influenza, noted a blog in the Los Angeles Times posted Dec. 30.
Such closures are based on the idea that such institutions are fertile places for viruses to spread and that children then carry the viruses into the community, but their use has been controversial because of the burden placed on parents and the educational system.
The Centers for Disease Control and Prevention now recommends that school closings occur only in limited circumstances.
Dr. Bruce Lee, an epidemiologist at the University of Pittsburgh, and his colleagues used computer modeling based on Allegheny County, Pa., to simulate various scenarios.
The researchers concluded that closing schools for up to two weeks might delay the peak of an outbreak slightly but that, at worst, it might increase transmission by dumping susceptible children back into schools in the middle of an epidemic when they are most vulnerable to infection. To be effective, the closures had to last for at least eight weeks, they concluded. They also found that isolating sick kids individually and keeping them from attending school also had little impact on the course of the epidemic.
Results from an Australian study published in the online journal Emerging Infectious Diseases support this conclusion, although for different reasons. Dr. Paul V. Effler and his colleagues from the Department of Health in Perth, Australia, studied the activity of 233 kids during a school closing prompted by an H1N1 flu outbreak and concluded that the closing did little to keep the kids out of contact with one another.