Effects of School Closure on Incidence of Pandemic Influenza in Alberta, Canada FREE

Influenza (“the flu”) is a virus that spreads from person to person through coughing and sneezing. Keeping infected persons away from others may slow an influenza epidemic or even prevent one from occurring. Influenza may start to spread in a community mainly through schoolchildren. Communities often close schools to try to lessen the effect of influenza, but it has been hard to prove that this technique really works.

In the spring of 2009, a new strain of influenza emerged. Because a large segment of the population did not have natural immunity (protection by their immune system), the virus spread rapidly around the world. This allowed scientists to study how this new strain of influenza spread and how the planned closing of schools for the summer break affected the spread of the virus.

In Alberta, Canada, a province with 3.7 million people, patients with symptoms that suggested influenza who sought health care from April to October 2009—a much longer period of testing than that in the United States or other parts of Canada—were routinely tested for the new influenza virus (and other viruses that cause colds and flu-like illnesses) More than 35 000 samples were obtained during this time. Researchers recorded influenza test results by date, age, and location and looked at data on weather patterns. They also noted when schools closed for the summer and opened for the fall term in various parts of the province. These data were put into mathematical models to predict what factors affected influenza transmission.

Closing schools for the summer break dramatically decreased the spread of influenza in the community. Changes in temperature also affected the number of cases of influenza that occurred, but to a much smaller degree.

The results are based on mathematical models applied to natural observations; such results are less reliable than those based on controlled experiments.

Closing schools may reduce spread of influenza and the number of infected people. Well-planned school closure may therefore be an effective tool for communities to combat influenza. However, the benefits of school closure need to be weighed against the negative effects, such as disrupting educational programs and forcing some parents to miss work.