Department of Mathematics, Konkuk University, Seoul, Korea.
Division of Infectious Disease, Department of Internal Medicine, Kangnam Sacred Heart Hospital, Hallym University College of Medicine, Seoul, Korea.
Epidemiol Health. 2021;43:e2021059. doi: 10.4178/epih.e2021059. Epub 2021 Sep 8.
This study aims to analyze the possibility and conditions of maintaining an effective reproductive number below 1 using a mathematical model.
The total population was divided into five age groups (0-17, 18-29, 30-59, 60-74, and ≥75 years). Maximum likelihood estimation (MLE) was used to estimate the transmission rate of each age group. Mathematical model simulation was conducted until December 31, 2021, by establishing various strategies for vaccination and social distancing without considering variants.
MLE results revealed that the group aged 0-17 years had a lower risk of transmission than other age groups, and the older age group had relatively high risks of infection. If 70% of the population will be vaccinated by the end of 2021, then simulations showed that even if social distancing was eased, the effective reproductive number would remain below 1 near August if it was not at the level of the third re-spreading period. However, if social distancing was eased and it reached the level of the re-spreading period, the effective reproductive number could be below 1 at the end of 2021.
Considering both stable and worsened situations, simulation results emphasized that sufficient vaccine supply and control of the epidemic by maintaining social distancing to prevent an outbreak at the level of the re-spreading period are necessary to minimize mortality and maintain the effective reproductive number below 1.
本研究旨在通过数学模型分析维持有效繁殖数低于 1 的可能性和条件。
将总人口分为五个年龄组（0-17 岁、18-29 岁、30-59 岁、60-74 岁和≥75 岁）。采用最大似然估计（MLE）估计各年龄组的传播率。通过建立不考虑变异的各种疫苗接种和社交距离策略，进行数学模型模拟，模拟时间截至 2021 年 12 月 31 日。
MLE 结果表明，0-17 岁年龄组的传播风险低于其他年龄组，而年龄较大的年龄组感染风险相对较高。如果到 2021 年底，70%的人口将接种疫苗，那么即使放宽社交距离限制，在 8 月之前，模拟结果显示，如果没有达到第三次再传播期的水平，有效繁殖数仍将保持在 1 以下。然而，如果放宽社交距离限制并达到再传播期的水平，那么在 2021 年底有效繁殖数可能会低于 1。
考虑到稳定和恶化的情况，模拟结果强调，为了最大限度地降低死亡率并保持有效繁殖数低于 1，有必要提供足够的疫苗供应，并通过保持社交距离来控制疫情，以防止再传播期的爆发。
