Evaluation of intervention strategies in schools including ventilation for influenza transmission control

Many common respiratory infectious diseases transmit readily among school-age children. In major epidemics, school closures and class suspensions may be implemented to attempt to control transmission in the community. However, such intervention measures have been subject to an extensive debate as well as questions of its effectiveness and adverse social impacts. In the meanwhile, engineering intervention methods are also available, but their impacts at the community level were not well studied. A better understanding of how different school interventions contribute to the airborne disease prevention can provide public health officials important information to design infection control strategies, in particular how engineering control methods such as ventilation are compared to other intervention methods. In this study a hypothetical indoor social contact network was constructed based on census and statistical data of Hong Kong. Detailed school contact structures were modeled and predicted. Influenza outbreaks were simulated within indoor contact networks, allowing for airborne transmission. Local infection risks were calculated from the modified Wells-Riley equation, and the transmission dynamics of the disease were simulated using the SEPIR model. Both school-based general public health interventions (such as school closures, household isolation) and engineering control methods (including increasing ventilation rate in schools and homes) were evaluated in this study. The results showed that among different school-based interventions, increasing ventilation rate together with household isolation could be as effective as school closure.