西安市新型冠状病毒肺炎聚集性疫情流行特征

目的 分析西安市新型冠状病毒肺炎（COVID-19）典型聚集性疫情的传播特征,为优化疫情防控策略提供科学依据。方法 采用Excel、SPSS软件对西安市典型聚集性疫情进行描述性流行病学分析;并分析病例的代际传播和潜伏期。结果 西安市截至2020年3月31日累计报告COVID-19典型聚集性疫情8起,涉及确诊病例53例、无症状感染者15例,死亡1例;以聚餐聚会引起的疫情为主,占37.50%,总体罹患率为14.21%。疫情累计持续时间中位数 27 d,5个区的24个街道办事处/乡镇有聚集性病例,男性确诊病例和无症状感染者数均略多于女性,无症状感染者平均年龄（54岁）大于确诊病例（46岁）。疫情一代病例与二代病例的代际间隔平均为6.8 d（95%CI: 5.8~7.5）,中位数为 5.6 d。由3起疫情推算的潜伏期平均为7.9 d。结论 西安市典型聚集性疫情以聚会聚餐型为主,应做好重点地区、重点人群的自我防护和隔离,避免密切接触等措施,以减少COVID-19聚集性疫情的发生。

Epidemiological characteristics of the clusters of COVID-19 in Xi'an

Objective To explore the transmission characteristics of the typical clusters of coronavirus diseases 2019 (COVID-19) in Xi'an, so as to provide scientific basis for optimizing the control strategy of COVID-19. Methods Statistical tools as Excel, SPSS software were used to describe the distribution of the typical clusters, the latent period as well as intergenerational transmission. Results By March 31th, 2020, a total of 8 clusters of COVID-19 were occurred in Xi'an, with 53 confirmed cases, 15 cases of asymptomatic infection, and one death, as well as total attack rate with 14.21%, of which 37.50% clusters occurred in party or dinner. The cumulative duration of the clusters was 27 days, clusters of cases were distributed in 24 subdistricts of the 5 districts of Xi'an city. Both the male confirmed cases and asymptomatic cases were slightly higher than that of female, but the average age of asymptomatic cases (54 years old) was older than that of confirmed cases (46 years old) . The average interval between the first and second generation cases was 6.8 days (95%CI:5.8-7.5) , and the median was 5.6 days. The average length of the incubation period was 7.9 days from three clusters of COVID-19 in Xi'an. Conclusion The main clusters of COVID-19 occurred in party or dinner in Xi'an, measures such as self-protection,isolation as well as avoiding close contact of key areas and key population should be taken to, in order to reduce the clusters of COVID-19.