衡阳市新型冠状病毒肺炎流行病学特征分析及防控措施评估

目的 描述和分析衡阳市新型冠状病毒肺炎(简称新冠肺炎,COVID-19)流行病学特征,初步评估防控措施效果。方法 选取自《中国疾病预防控制信息系统》网络直报的衡阳市新冠肺炎确诊病例和无症状感染者数据,回顾性描述衡阳市疫情概况、三间分布,分析新冠肺炎流行特征;使用SIR(susceptible infected recovered)模型,并用Python 求解微分方程,根据预测值和实际值的差异评估衡阳市防控措施的有效性。结果 衡阳市从2020年1月25日报告首例确诊病例开始,截至3月2日,累计报告新冠肺炎确诊病例和无症状感染者54例,其中无症状感染者6例(11.11%);输入病例32例(59.25%),本地病例22例(40.75%);男性病例35例,女性病例19例,男女比例1.84∶1;年龄以30~60岁居多,为40例(74.1%);职业分布中,农民/农村务工人员占大多数为18例(33.33%);流行曲线显示确诊病例多集中在1月23—30日之间发病,此后散在发生;除南岳区外,衡阳市所有县市区均有确诊病例;患者临床表现多有发热,共44例,咳嗽26例;CT检查有肺部影像学改变的46例(95.83%);将新冠肺炎疫情确诊数和出院数带入SIR模型,实际确诊数较模型预测确诊数少,提示衡阳市防控措施有效。结论 衡阳市疫情目前处于平缓下降时期,这得益于防控措施的有力实施,但随着境外病例输入的增多和本地复工复产复学的人口流动扩大,要进一步加强疫情监测和管理。

Epidemiological characteristics of coronavirus disease 2019 and evaluation of its prevention and control measures in Hengyang city

Objective To describe and analyze the epidemiological features of coronavirus disease 2019 (COVID-19) in Hengyang city, and to preliminarily evaluate the effectiveness of its prevention and control measures. Methods We selected COVID-19 confirmed cases and asymptomatic cases network-directly reported in Hengyang city from China Information System for Disease Prevention and Control, retrospectively described the three-dimensional distribution of epidemic situation in Hengyang city, and analyzed the epidemic characteristics of COVID-19. Susceptible infected recovered (SIR) model was used in this study, Python was employed to solve the differential equation, and the effectiveness of prevention and control measures in Hengyang city was evaluated according to the difference between the predictive value and the actual value. Results Fifty-four confirmed cases and asymptomatic cases were accumulatively reported in Hengyang city from January 25, 2020 when the first confirmed case was reported in Hengyang city to March 2, 2020, of which 6 (11.11%) cases were asymptomatic. 32 (59.25%) imported cases and 22 (40.75%) local cases were reported. There were 35 male cases and 19 female cases, and the male-to-female ratio was 1.84∶1. Most of the cases (40/54, 74.1%) ranged in age from 30 to 60 years. Occupation distribution showed that the majority of the cases (18/54, 33.33%) were farmers/rural migrant workers. The epidemic curve revealed that the confirmed cases mainly occurred between January 23 and 30, and then occurred sporadically. All counties/cities/districts in Hengyang city reported confirmed cases except Nanyue district.The main clinical manifestation of the patients was fever (44/54), and 26 patients had a cough. Chest CT displayed 46 (95.83%) cases with patchy increased density shadow in lungs. The number of COVID-19 confirmed cases and the number of discharged cases were introduced into the SIR model, and the number of actually confirmed cases was less than the number of confirmed cases predicted by the model, indicating that prevention and control measures in Hengyang city were effective. Conclusions The COVID-19 epidemic in Hengyang city shows a slowdown trend at present, which have benefited from effectively implementing prevention and control measures. It is still necessary to further enhance epidemic surveillance and management on account of the increase of importation of cases from abroad and the increasing population mobility due to local people going back to work and schools.