COVID-19 testing systems and their effectiveness in small, semi-isolated groups for sports events.

In this study, we quantitatively assessed the effectiveness of systems for COVID-19 testing in small groups of sport teams that are semi-isolated from the general population by countermeasures against infection. Two types of group were assumed, and the dynamics of infection within each group was modeled by using a compartment model of infectious disease. One group (Group A) comprised domestic professional sports teams that play many games over a season while remaining within a relatively small region. Polymerase chain reaction (PCR) tests were routinely conducted once every 2 weeks, and the number of infected individuals that could not be quarantined after identification by testing or checking for symptoms was defined as the risk. The other group (Group B) comprised teams that travel across borders for mass-gathering events like the Olympic and Paralympic Games. The teams were isolated for 2 weeks at their destination; frequent testing and checking for symptoms was conducted, and any infected individuals were quarantined. The number of infected individuals participating in games after the isolation period was defined as the risk. In Group A, the number of infected individuals detected by routinely conducted PCR testing was lower than the number of infected individuals detected by checking for symptoms, indicating that routine testing every 2 weeks was not very effective. In Group B, daily PCR testing was the most effective, followed by daily antigen testing. Dual testing, in which individuals with a positive antigen test were given an additional PCR test, was the least effective with an effect equal to PCR testing every other day. These results indicate that repeated testing does not necessarily increase the detection of infected individuals.

Déclaration de conflit d'intérêts

This study was conducted as part of a comprehensive research project, comprising members from two private companies, Kao Corporation and NVIDIA Corporation, Japan. These members from the companies are not included as the author of this study. W.N. received financial support from the Kao Corporation until March 2020 in a context outside the submitted work. T.Y. and W.N. have received financial support from the Kao Corporation for a collaborative research project in the context of measures at mass-gathering events. T.Y. and W.N. have received financial support from the Yomiuri Giants, the Japan Professional Football League, and the Japan Professional Basketball League. M.K., M.M., T.Y. W.N, and S.I. have attended the New Coronavirus Countermeasures Liaison Council jointly established by the Nippon Professional Baseball Organization and the Japan Professional Football League as experts without any reward. T.Y. and W.N. are advisors to the Japan National Stadium. The findings and conclusions of this article are solely the responsibility of the authors and do not represent the official views of any institution.