Transmission of COVID-19 Under Non-Closed-Loop Management During Beijing 2022 Olympic and Paralympic Winter Games in China: A Modelling Study

Background: In response to worries that a strict closed-loop management might affect athletes' physical and mental states, and therefore their final competition performance, we attempted to simulate the scenarios in the Beijing 2022 Olympic and Paralympic Winter Games under the non-closed-loop management (NCLM) in order to predict whether NCLM will lead to the large-scale spread of COVID-19 in China.Methods: We assumed that foreign event-related personnel (AAO) and local community residents would adhere to non-pharmaceutical interventions (NPIs), including surveillance and contact tracing strategies. The optima nucleic acid test (NAT) strategy was estimated by a Markov Model. Different schemes in the Beijing 2022 Olympic and Paralympic Winter Games under NCLM were simulated by a compartmental model according to different background infection rates of AAO, the effectiveness of vaccine and vaccination rate of local community residents. The total number of infections and detection rate both in AAO and local residents during the period of 40-day were calculated respectively.Findings: A total of 567 schemes of NCLM in the Beijing 2022 Olympic and Paralympic Winter Games were simulated. If the local community was universally fully vaccinated with an effectiveness against infection of 50%, the optimal NAT strategy for AAO were once every three days, every other day, and daily according to their background infectious rates of 0.10%, 0.20-0.50% and more than 0.70% at entrance respectively. The total number of infections rising from AAO and local community residents were respectively 6.00-120.02 cases and 20.34-307.33 cases, while the detection rates were 96.20-97.61% and 85.95-85.97% respectively in AAO and local community residents. The transmission of COVID-19 caused by AAO traveling across mainland China is similar to that caused by local travel in Beijing and Hebei where the Beijing 2022 Olympic and Paralympic Winter Games will be held. In any optimal scheme, local community residents need a weekly NAT, and limit their daily contacts below 7 persons.Interpretation: It might be a manageable choice to implement NCLM in the upcoming Beijing 2022 Olympic and Paralympic Winter Games.Funding Information: NSCF (No. 91546203, 72174004) and the Ministry of Science and Technology of the People's Republic of China (No. 2021YFF0306004).Declaration of Interests: The authors declare that they have no competing interests.