Estimating New Cases Among Athletes During the Winter Olympics Based on a Dynamic Model — Beijing, China, February 2022

INTRODUCTION: Since first appearing in late 2021, the Omicron variant has spread rapidly around the world. Nevertheless, the XXIV Winter Olympic Games (WOG) were held in Beijing in February 2022, which undoubtedly posed a huge challenge to domestic epidemic prevention and control. METHODS: To analyze and evaluate the spread of the epidemic within the closed-loop management of the Beijing 2022 WOG, an improved dynamics model was established. Using the known dynamics parameters, the new daily cases and final members of quarantined people were predicted, and the influence of different factors on the change of the number of quarantined people was analyzed. RESULTS: When the proportion of exposed persons being detected and the degree of admixture between the two populations varied between 0.5 and 0.9, there was little change in the daily predicted number of new cases and the final number of quarantined patients. As the initial value of the exposed among inbound personnel increased, the final size of quarantined patients increased proportionally. DISCUSSION: From the analysis results, detecting potential virus carriers at the entry stage is the most effective way to control the spread of the epidemic within the closed-loop management of the Beijing 2022 WOG.