Hong Kong Special Administrative Region (SAR), China and Singapore are both facing considerable Omicron variant epidemic. However, the overwhelmed medical system and high case fatality ratio (CFR) just occurred in Hong Kong SAR, China but not in Singapore.

The low vaccination coverage in Hong Kong SAR, China, especially among the older adults, is shown to be a primary reason of its recent high CFR.

Facing the potential epidemic risk, non-vaccinated, non-fully-vaccinated, and non-booster-vaccinated people in China, especially the elderly, should get any type of accessible vaccine, which could save lives when the infection unfortunately befalls.

Many regions in China have recently reported outbreaks of the coronavirus disease 2019 (COVID-19) caused by the Omicron variant.

Wuchuan County, Guizhou Province reacted quickly and implemented accurate intervention measures to effectively control the outbreak. The susceptible-exposed-infectious-asymptomatic-removed (SEIAR) model was applied to evaluate the effectiveness of intervention measures.

Fast response measures should be taken to prevent the spread of outbreaks caused by the Omicron variant.

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.

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.

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 increases, the final size of quarantined patients increased proportionally.

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.