厦门市新型冠状病毒肺炎人群传播能力计算与防控措施效果的模拟评估

Estimating the transmissibility of coronavirus disease 2019 and assessing the effectiveness of the countermeasures to control the disease in Xiamen City

为计算厦门市新型冠状病毒肺炎(COVID-19)人群传播能力并模拟评估防控措施效果,根据COVID-19自然史构建厦门市COVID-19人群传播的易感者-潜伏者-染病者-隐性感染者-移出者(susceptible-exposed-infectious-asymptomaticrecovered,SEIAR)模型,收集厦门市截至2020年3月7日的COVID-19病例数据建立数据库,将SEIAR模型与数据库拟合计算COVID-19有效再生数(effective reproduction number,Reff),模拟综合干预措施情况下的流行曲线,并评估综合干预措施效果.截至3月7日厦门市共报告COVID-19病例35例,其中输入病例22例,继发病例13例,模型与疫情数据拟合结果较好(χ^2=10.375,p=0.996).模型结果显示:1月26日之前,COVID-19在厦门市的Reff为2.78,1月26日之后的Reff为0.35,综合干预措施将Reff降低了87.41%.若1月26日未强化综合干预措施,则截至3月7日预计累计报告病例和本地病例将分别达到1863和1841例,而实际累计报告病例和本地病例分别为35和13例,分别降低了98.12%和99.29%.上述结果表明厦门市COVID-19人群传播能力较强,综合干预措施取得了较好的防控效果.

To evaluate the transmissibility of coronavirus disease 2019(COVID-19)and the effectiveness of countermeasures in Xiamen City,a susceptible-exposed-infectious-asymptomatic-recovered(SEIAR)model was developed according to the natural history of COVID-19.The data of the reported COVID-19 cases were collected as of March 7 th,2020 in Xiamen City.The SEIAR model was employed to fit the data,to calculate the effective reproduction number(Reff),and to assess the effectiveness of combined intervention measures accordingly.The results showed that a total of 35 COVID-19 cases were reported in Xiamen City,among which22 cases were imported and 13 cases were secondary infected.The SEIAR model fitted the reported data significantly well(χ^2=10.375,p=0.996).The values of Reff before and after January 26 th were 2.78 and 0.35,respectively.The combined countermeasures reduced the Reffby 87.41%.If the intervention were not strengthened on January 26 th,the cumulative number of reported cases and local cases would be expected to have reached 1863 and 1841 as of March 7 th,and the actual cumulative number of reported cases and local cases were 35 and 13,respectively,with a decrease of 98.12%and 99.29%,respectively.Taken together,the COVID-19 has a strong transmissibility in Xiamen City,and combined countermeasures have achieved good effectiveness to control the transmission of the virus.