Rotation-based schedules in elementary schools to prevent COVID-19 spread: A simulation study

BackgroundRotations of schoolchildren on a weekly basis is one of the nonpharmaceutical interventions often considered in the covid-19 pandemic. This study aims to investigate the impact of different types of rotations in various testing contexts. MethodsWe built an agent-based model of interactions among pupils and teachers based on an online survey in an elementary school in Prague, Czechia. This model contains 624 schoolchildren and 55 teachers (679 nodes) and about 27 thousands social contacts (edges) in 10 layers. The layers reflect different types of contacts (in classroom, cafeteria etc.) as described in the survey. On this multi-graph structure we run a modified SEIR model of the covid-19 dynamics. The parameters of the model are calibrated on data from the outbreak in the Czech Republic in the period March to June 2020. FindingsThere are three main findings in our paper. O_LIWeekly rotations of in-class and distance learning reduce the spread of covid-19 by 75-81% and thus represent an effective preventative measure in school setting. C_LIO_LIRegular antigen testing twice a week, or weekly PCR testing, significantly reduces infections even when using tests with a lower sensitivity: tests with a 40% sensitivity reduce infections by more than 50 percent. C_LIO_LIThe density of revealed contact graphs for older pupils is 1.5 times higher than the younger pupils graph, the teachers network is yet an order of magnitude denser. Consequently, the infection transmission between teachers is highly overproportional in our school. Moreover, teachers act as bridges connecting clusters of classes, especially in the secondary grade where they are responsible for 14-18% of infections, in comparison to 8-11% in primary grade. C_LI InterpretationWeekly rotations with regular testing are a highly effective non-pharmaceutical intervention for the prevention of covid-19 spread in schools and a way to keep schools open during an epidemic or to reopen them as the epidemiological situation improves.