深圳市新型冠状病毒肺炎应急响应策略和措施效果评价

目的 对深圳市新型冠状病毒肺炎（新冠肺炎）应急响应策略和措施的效果进行评价，明确人口密度高、流动性强的超大城市新冠肺炎策略和措施的有效性。方法 绘制新冠肺炎流行曲线，划分流行期和防控阶段，观察防控措施效果。制作双层阶发病标点地图，明确不同时点传染源的分布和传播风险。建立传播动力学模型，预期发病数与实际发病数对比。新型冠状病毒核酸检测阳性率，反映人群风险水平。借助深圳市人群新冠肺炎相关知识、态度和行为调查结果，估计人群防护和响应能力。结果 深圳市新冠肺炎流行经历了上升期、平台期和下降期，疫情上升快，但高峰期持续时间短，而发病降低的速度快和幅度大；流行曲线虽然呈现人传人现象，但“拖尾”现象不明显。从发病标点地图看，在新冠肺炎防控干预期，传染源分布广泛；人口密度越高的区域，病例数越多；而防控干预措施见效后，传染源减少。从预期发病数对比可见，实际病例数大幅减少。高危险人群新型冠状病毒核酸检测阳性率呈下降趋势，2月16日之后未能检出。市民新冠肺炎知识、态度和行为水平较高，防护能力和应急响应度较高。结论 深圳市早期由部门主导的防控机制发挥了重要作用，但不足以阻断新冠肺炎流行；一级响应策略和措施效果明显，确保了春节后复工复产的启动；对超大城市，采取综合性阻断策略和措施，同样可以控制新冠肺炎的流行。

Evaluation of the emergency response strategies and measures on the epidemic of COVID-19 in Shenzhen, China

Objectives This study aimed to evaluate the effect of the strategies on COVID-19 outbreak control in Shenzhen, and to clarify the feasibility of these strategies in metropolitans that have high population density and strong mobility. Methods The epidemic feature of COVID-19 was described by different phases and was used to observe the effectiveness of intervention. Hierarchical spot map was drawn to clarify the distribution and transmission risk of infection sources at different time points. The Susceptible-Exposed-Infectious-Asymptomatic-Recovered model was established to estimate case numbers without intervention and compare with the actual number of cases to determine the effect of intervention. The positive rate of the nucleic acid test was used to reflect the risk of human exposure. A survey on COVID-19 related knowledge, attitude and behaviors were used to estimate the abilities of personal protection and emergency response. Results The epidemic of COVID-19 in Shenzhen experienced the rising, plateau and decline stage. The case number increased rapidly at the beginning, with short duration of peak period. Although the epidemic curve showed human-to-human transmission, the "trailing" was not obvious. From the spot map, during the intervention period, the source of infection was widely distributed. More cases and higher transmission risk were observed in areas with higher population density. After the effective intervention measures, both infection sources and the risk of transmission decreased. After compared with the estimated case numbers without intervention, actual number proved the COVID-19 control strategies were effective. The positive rate of nucleic acid test for high risk populations decreased and no new cases reported since February 16. Shenzhen citizens had high knowledge, attitude and behavior level, and high protection ability and emergency response. Conclusions Although the response initiated by the health administration department played a key role at the early stage of the epidemic, it was not enough to contain the outbreak of COVID-19. The first-level emergency response initiated by provincial and municipal government was effective and ensured the start of work resumption after the Spring Festival. Metropolitans like Shenzhen can also achieve the goals of strategies and measures for containment and mitigation of COVID-19.