针对新型冠状病毒肺炎隔离措施的动力学评估

Dynamic assessment of isolation measures for COVID-19

针对2019年底暴发的新型冠状病毒肺炎,中国政府采取了一系列严格的防控措施,其中起关键作用的是普通民众的居家隔离与密切接触者的追踪隔离.建立新型冠状病毒传播与控制动力学模型,定量评估这两项措施的有效性.利用下一代矩阵法计算了基本再生数和有效再生数,给出了有效再生数的极限范围,分析了模型的动力学特征.以安徽省为例,利用MCMC(Markov chain Monte Carlo)参数估计方法进行数值拟合,得到安徽省新型冠状病毒传播模型的基本再生数为0.4021(95%CI:0.3973~-0.4070),有效再生数的极限范围为[0,0.048745].随着隔离措施的有效实施,安徽省的有效再生数迅速下降到0.05以下并趋于0.048735,疫情及时得到了控制.如果没有采取这些隔离措施,基本再生数为2.1030(95%CI:2.0804~2.1255),疾病将会在人群中持续传播.通过参数敏感性分析,发现加强密切跟踪隔离力度,即增加染病者的隔离速率系数,能够有效降低基本再生数;加强居家隔离力度,即增加易感者的隔离速率系数与减少易感者的隔离解除速率系数,有助于降低有效再生数极限范围的上界.

In response to the COVID-19 outbreak at the end of 2019,the Chinese government adopted a series of strict prevention and control measures,among which the key role was the isolation of ordinary people at home and the tracing and quarantine of close contacts.It set up a transmission and control dynamics model to quantitatively evaluate the effectiveness of these measures.The basic regeneration number and effective regeneration number were calculated by the next generation matrix method,and the range of the limit of effective regeneration number was given.The dynamic characteristics of the model were analyzed.Taking Anhui province as an example,the MCMC parameter estimation method was used for numerical fitting.The basic regeneration number of Anhui province was obtained as 0.4021(95%confidence interval:0.3973~0.4070).The range of the limit of effective regeneration number was given by[0,0.048745].With the effective implementation of quarantine measures,the effective regeneration number in Anhui province rapidly dropped below 0.05 and tended to 0.048735.The epidemic situation was brought under control in time.Without these quarantine measures,the basic reproductive number was 2.1030(95%confidence interval:2.0804~2.1255).The disease spread persistently in the population.Through parameter sensitivity analysis,it was found that strengthening the quarantine intensity of close tracking,in other words,increasing the isolation rate coefficient of infected persons,could effectively reduce the basic regeneration number.Strengthening the home isolation,in other words,increasing the isolation rate coefficient of susceptible persons and reducing the isolation release rate coefficient of susceptible persons,was helpful to reduce the upper limit of the range of the limit of the effective regeneration number.