Kyushu University, Fukuoka, 819-0395, Japan.
Research Institute for Science Education, Inc., Kyoto, 603-8346, Japan.
Sci Rep. 2021 Jan 21;11(1):1936. doi: 10.1038/s41598-021-81521-z.
Exploiting the SIQR model for COVID-19, I show that the wavy infection curve in Japan is the result of fluctuation of policy on isolation measure imposed by the government and obeyed by citizens. Assuming the infection coefficient be a two-valued function of the number of daily confirmed new cases, I show that when the removal rate of infected individuals is between these two values, the wavy infection curve is self-organized. On the basis of the infection curve, I classify the outbreak of COVID-19 into five types and show that these differences can be related to the relative magnitude of the transmission coefficient and the quarantine rate of infected individuals.
利用 SIQR 模型研究 COVID-19，我发现日本感染曲线的波动是政府隔离措施的政策波动和民众遵守程度的结果。假设感染系数是每日新增确诊病例数的双值函数，我发现当感染个体的清除率在这两个值之间时，感染曲线是自组织的。基于感染曲线，我将 COVID-19 的爆发分为五种类型，并表明这些差异可能与传播系数和感染个体的隔离率的相对大小有关。
