Hong H, Shi H B, Jiang H B, Gu X M, Chen Y, Ding K Q, Xu G Z
Institute for AIDS/STD Prevention and Control, Institute for Communicable Disease Prevention and Control, Ningbo City Center for Disease Control and Prevention, Ningbo 315010, China.
Zhonghua Liu Xing Bing Xue Za Zhi. 2020 Oct 10;41(10):1606-1610. doi: 10.3760/cma.j.cn112338-20200311-00313.
To evaluate effectiveness of prevention and control strategies for COVID-19 in Ningbo by using an epidemic dynamic model. The incidence data and epidemic information of COVID-19 reported in Ningbo as of 9 March, 2020 were collected, and based on the implementation of prevention and control strategies, we developed a SEIR epidemic dynamics model. The basic and real-time reproduction numbers were calculated to evaluate effectiveness of prevention and control. A total of 157 cases of COVID-19 were confirmed, without death, in Ningbo. The proportion of severe cases was 12.1. The mean incubation period was estimated to be (5.7±2.9) days. The mean interval from illness onset to diagnosis was (5.4±3.7) days. The mean duration from diagnosis to hospital discharge was (16.6±6.5) days. A total of 105 339 contacts had been under medical observation. The infection rates in contacts with home quarantine and centralized quarantine were 0.1 and 0.3, respectively. In the confirmed cases, those who had been under medical observation before diagnoses accounted for 63.1. The basic reproduction number was estimated to be 4.8. With the strengthening of prevention and control measures, real-time reproduction number showed a gradual downward trend, dropping to below 1.0 on 4 February, and then continued to drop to 0.2 in mid-February. The effectiveness of the prevention and control measures for COVID-19 in Ningbo can be evaluated by using epidemic dynamic model to provide scientific evidence for the development of the prevention and control strategies.
运用疫情动态模型评估宁波市新型冠状病毒肺炎防控策略的效果。收集截至2020年3月9日宁波市报告的新型冠状病毒肺炎发病数据及疫情信息，基于防控策略的实施情况，构建了SEIR疫情动力学模型。计算基本再生数和实时再生数以评估防控效果。宁波市共确诊新型冠状病毒肺炎病例157例，无死亡病例。重症病例比例为12.1%。平均潜伏期估计为(5.7±2.9)天。发病至诊断的平均间隔为(5.4±3.7)天。诊断至出院的平均病程为(16.6±6.5)天。共对105339名密切接触者进行了医学观察。居家隔离和集中隔离密切接触者的感染率分别为0.1%和0.3%。确诊病例中，诊断前接受医学观察的占63.1%。基本再生数估计为4.8。随着防控措施的加强，实时再生数呈逐渐下降趋势，2月4日降至1.0以下，2月中旬继续降至0.2。运用疫情动态模型可评估宁波市新型冠状病毒肺炎防控措施的效果，为防控策略的制定提供科学依据。
