The Effectiveness of Class Closure During N1H1 Influenza Pandemics

Abstract

The effectiveness of class closure during N1H1 influenza pandemics was examined. The number and the rates of absentees from school were investigated using the records of 22 classes of an elementary school in Osaka Prefecture from August 27, 2009 to February 25, 2010.

The periods of the class closure recommended by board of education were at least 4 days. Therefore, the class closure was usually decided on the absence rate on Monday. In this study, the classes were divided into two groups: the class closure group (n=8) and the non class closure group (n=11). The former group implemented class closure between Monday afternoon and Friday including Saturday and Sunday when the influenza absence rate exceeded 5.7% on Monday: the students were able to rest for six days totally. The latter group did not implement class closure despite over 5.7% of influenza absence rate on Monday: the students had lessons from Monday to Friday and two holidays on Saturday and Sunday. The differences of the absence rate between Monday and next Monday in class closure group were compared with those in non class closure group.

During the study period, the class closure reached 16 times totally and occurred 8 times on Monday. The improvement rate of attendance in the class closure group was significantly higher than that in the non class closure group(p＜0.05).

These results suggest that the implementation of class closure decided on the absence rate of over 5.7% on Monday might have beneficial effect on class attendance of next week.