Sun Jiaqi, Li Yusi, Xiao Lin-Fan, Shao Ning-Yi, Liu Miao
Department of Mathematics, Faculty of Science and Technology, University of Macau, Taipa, Macau, China.
Department of Biomedical Sciences, Faculty of Health Sciences, University of Macau, Taipa, Macau, China.
Vaccines (Basel). 2023 May 22;11(5):1009. doi: 10.3390/vaccines11051009.
China is relaxing COVID-19 measures from the "dynamic zero tolerance" (DZT) level. The "flatten-the-curve" (FTC) strategy, which decreases and maintains the low rate of infection to avoid overwhelming the healthcare system by adopting relaxed nonpharmaceutical interventions (NPIs) after the outbreak, has been perceived as the most appropriate and effective method in preventing the spread of the Omicron variant. Hence, we established an improved data-driven model of Omicron transmission based on the age-structured stochastic compartmental susceptible-latent-infectious-removed-susceptible model constructed by Cai to deduce the overall prevention effect throughout China. At the current level of immunity without the application of any NPIs, more than 1.27 billion (including asymptomatic individuals) were infected within 90 days. Moreover, the Omicron outbreak would result in 1.49 million deaths within 180 days. The application of FTC could decrease the number of deaths by 36.91% within 360 days. The strict implementation of FTC policy combined with completed vaccination and drug use, which only resulted in 0.19 million deaths in an age-stratified model, will help end the pandemic within about 240 days. The pandemic would be successfully controlled within a shorter period of time without a high fatality rate; therefore, the FTC policy could be strictly implemented through enhancement of immunity and drug use.
中国正在从“动态清零”水平放宽新冠疫情防控措施。“曲线平缓化”（FTC）策略，即在疫情爆发后通过采取宽松的非药物干预措施（NPIs）来降低并维持低感染率，以避免医疗系统不堪重负，已被视为预防奥密克戎变异株传播的最合适、最有效的方法。因此，我们基于蔡构建的年龄结构随机分区易感-潜伏-感染-康复-易感模型，建立了一个改进的数据驱动的奥密克戎传播模型，以推断全中国的总体预防效果。在当前未应用任何NPIs的免疫水平下，90天内超过12.7亿人（包括无症状感染者）被感染。此外，奥密克戎疫情在180天内将导致149万人死亡。应用FTC可在360天内将死亡人数减少36.91%。在年龄分层模型中，严格实施FTC政策并结合完成疫苗接种和药物使用，仅导致19万人死亡，这将有助于在约240天内结束疫情。疫情将在更短时间内得到成功控制，且不会出现高死亡率；因此，可通过增强免疫力和使用药物来严格实施FTC政策。
