Epidemic characteristics of a local SARS-CoV-2 outbreak caused by Omicron variant (BA.2.3) in Yantai City
LIU Xiuwei1, LIN Jingtao2, HOU Shuting1, YU Changlan1, LI Shanyawen1, LIU Jingyu1, HOU Minjun3
1. Yantai Municipal Center for Disease Control and Prevention, Yantai, Shandong 264003, China; 2. Qixia Center for Disease Control and Prevention, Qixia, Shandong 265300, China; 3. Zhaoyuan Center for Disease Control and Prevention, Zhaoyuan, Shandong 265400, China
Abstract：Objective To analyze the epidemic features of a local severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) outbreak caused by Omicron variant in Yantai City, and to provide a reference basis for prevention and control of the SARS-CoV-2 epidemic. Methods We collected the data regarding reported local cases of SARS-CoV-2 infection in Yantai City from April 22 to May 6, 2022. R4.2.1 software was used for data analysis. ArcGIS 10.2 software was employed to establish a database about geographical information concerning the cases of SARS-CoV-2 infection. Results Gene sequence analysis showed that the outbreak was caused by Omicron variant (BA.2.3), which spread to six districts and cities in Yantai City, namely Zhaoyuan City, Penglai District, Zhifu District, Qixia City, Kaifa District and Laizhou City. The outbreak lasted 15 days according to the reporteddate. A total of 210 infection cases were reported, including 100 males and 110 females. The ages ranged from 10 months to 94 years, with a median age of 52 years. There were 6 confirmed cases (including 1 minor patient and 5 common patients) and 204 asymptomatic infection cases. Most of the cases were exposed to direct contact, accounting for 75.24%. The main mode of case finding was centralized isolation (n=173). The incubation period ranged from 1 day to 6 days, and the median (M(P25, P75)) of the incubation period was 3.0 (2.5, 4.0) days. Rt reached the highest level of 9.35 on the 3rd day (April 24) after the prevention and control measures were taken, and then declined rapidly, and dropped below 1 on the 9th day (April 30). Conclusion This outbreak caused by highly transmissible Omicron variant had a short incubation period. The relevant departments should implement epidemic prevention and control measures in time, and it is of great significance to focus on the spread of the epidemic in key places for epidemic prevention and control.
刘秀玮, 林京涛, 侯舒婷, 禹长兰, 李善雅文, 刘靖宇, 侯民军. 烟台市一起由奥密克戎变异株BA.2.3引起的新冠感染本土疫情流行特征分析[J]. 实用预防医学, 2023, 30(11): 1329-1332.
LIU Xiuwei, LIN Jingtao, HOU Shuting, YU Changlan, LI Shanyawen, LIU Jingyu, HOU Minjun. Epidemic characteristics of a local SARS-CoV-2 outbreak caused by Omicron variant (BA.2.3) in Yantai City. , 2023, 30(11): 1329-1332.
2023, Vol. 30 
