Yang Jie, Tang Sanyi, Cheke Robert A
School of Mathematics and Information Science, Shaanxi Normal University, Xi'an, 710062 People's Republic of China.
Natural Resources Institute, University of Greenwich at Medway, Central Avenue, Chatham Maritime, Chatham, Kent ME4 4TB UK.
Nonlinear Dyn. 2021;104(1):863-882. doi: 10.1007/s11071-021-06294-6. Epub 2021 Feb 22.
By March 2020, China and Singapore had achieved remarkable results in the prevention and control of COVID-19, but in April Singapore's outbreak began to deteriorate, while China's remained controlled. Using detailed data from Tianjin, China, and Singapore, a stochastic discrete COVID-19 epidemic model was constructed to depict the impact of the epidemic. Parameter estimation and sensitivity analysis were developed to study the probability of imported cases inducing an outbreak in relation to different prevention and control efforts. Results show that the resumption of work and the re-opening of schools will not lead to an outbreak if the effective reproduction number is lower than 1 and approaches 0 and tracking quarantine measures are strengthened. Once an outbreak occurs, if close contacts can be tracked and quarantined in time, the outbreak will be contained. If work is resumed and schools are re-opened with the effective reproduction number greater than 1, then it is more likely that a secondary outbreak will be generated. Also, the greater the number of undetected foreign imported cases and the weaker the prevention and control measures, the more serious the epidemic. Therefore, the key to prevention of a second outbreak is to return to work and to re-open schools only after the effective reproduction number is less than 1 for a period, and when tracking quarantine measures have been strengthened. Our model provides a qualitative and quantitative basis for decision-making for the prevention and control of COVID-19 epidemics and the prediction, early warning and risk assessment of secondary outbreaks.
到2020年3月，中国和新加坡在新冠疫情防控方面取得了显著成效，但4月新加坡的疫情开始恶化，而中国的疫情仍得到控制。利用来自中国天津和新加坡的详细数据，构建了一个随机离散新冠疫情模型来描述疫情的影响。开展了参数估计和敏感性分析，以研究输入病例引发疫情的概率与不同防控措施之间的关系。结果表明，如果有效再生数低于1且趋近于0，并加强追踪检疫措施，复工和学校复课不会导致疫情爆发。一旦疫情发生，如果能及时追踪并隔离密切接触者，疫情将得到控制。如果在有效再生数大于1的情况下复工和学校复课，那么更有可能引发二次疫情。此外，未检测到的境外输入病例数量越多、防控措施越薄弱，疫情就越严重。因此，预防二次疫情爆发的关键在于，只有在有效再生数在一段时间内小于1且加强了追踪检疫措施之后，才恢复工作和学校复课。我们的模型为新冠疫情防控决策以及二次疫情爆发的预测、预警和风险评估提供了定性和定量依据。
