Effectiveness of Non-pharmaceutical Interventions in Controlling an Influenza A Outbreak in a School, Thailand, November 2007.

Non-pharmaceutical interventions are often recommended as a component of integrated control measures for pandemic influenza, but the effectiveness needs to be evaluated. An outbreak of influenza A (H1N1) in northern Thailand in November 2007 offered opportunity to evaluate these interventions. An investigation was conducted to describe the outbreak, evaluate effectiveness of non-pharmaceutical interventions and assess surge capacity of health agencies. A descriptive study was conducted by interviewing students and personnel in a school. We characterized transmission of the virus in this outbreak and explored effects of control measures. We identified that 44% of the students and teachers developed influenza during the 19-day outbreak. Non-pharmaceutical interventions including school closure, setting up a field hospital and community health education were implemented. These measures possibly limited the outbreak spreading to other schools nearby. Surveillance and preparedness plans could be strengthened to respond to pandemic and inter-pandemic influenza by using non-pharmaceutical interventions.