丹东市39969例新型冠状病毒肺炎病例密切接触者的继发感染情况及影响因素分析

Analysis of secondary infection and influencing factors of 39969 close contacts of COVID-19 cases in Dandong City

目的 分析辽宁省丹东市新型冠状病毒肺炎病例密切接触者的感染情况和影响因素,为密切接触者的判定、追踪和管理等疫情防控策略的调整和完善提供科学依据。方法 收集2022年4月24日至5月9日丹东市报告的新型冠状病毒肺炎确诊病例、无症状感染者以及密切接触者的流行病学资料,分析密切接触者中不同特征人群的感染风险差异和影响因素。结果 39 969例密切接触者中,有622例转归为确诊病例或无症状感染者,总感染率为1.56%。不同年龄组中≤20岁(3.73%)的密切接触者感染率较高(χ^(2)=312.11,P<0.001),不同接触方式中共同居住(22.62%)、同聚餐聚会(4.74%)、同空间学习(4.95%)感染率较高(χ^(2)=3135.58,P<0.001),末次暴露至指示病例发病日期间隔≤2 d(2.08%)感染率较高(χ^(2)=165.01,P<0.001),指示病例为确诊病例(5.49%)感染率较高(χ^(2)=411.32,P<0.001)。多因素Logistic回归分析显示,共同居住(OR:153.04,95%CI:70.64~331.56)、同聚餐聚会(OR:28.06,95%CI:12.36~63.73)、同空间学习(OR:14.79,95%CI:6.69~32.68)、共同工作(OR:12.35,95%CI:5.27~28.96)和指示病例为确诊病例(OR:2.65,95%CI:2.11~3.33)感染风险较高,21~40岁年龄组(OR:0.64,95%CI:0.46~0.89)、41~60岁年龄组(OR:0.56,95%CI:0.42~0.76)和末次暴露至病例发病或首阳间隔≥3 d(OR:0.68,95%CI:0.54~0.84)感染风险较低。结论 年龄、接触方式、与指示病例的末次暴露时间间隔、指示病例分类均为密切接触者感染的影响因素。共同居住、同聚餐聚会和同空间学习的感染率较高,加强密切接触者的精准判定和分类管理,对提高疫情防控效果具有重要意义。

Objective To analyze the infection status and influencing factors of close contacts of COVID-19 case in Dandong City of Liaoning Province,and to provide scientific basis for the adjustment and improvement of epidemic prevention and control strategies such as identification,tracking and management of close contacts.Methods The epidemiological data of COVID-19 case(including confirmed cases and asymptomatic case)and close contacts reported in Dandong City from April 24 to May 9,2022 was collected,and the differences in infection risk and influencing factors among groups with different characteristics were analyzed.Results Among the 39969 close contacts,about 622 cases were turned into confirmed cases or asymptomatic infections,with a total infection rate of 1.56%.In different age groups,the infection rate of close contacts aged≤20 years(3.73%)was higher(χ^(2)=312.11,P<0.001),living together(22.62%),eating together(4.74%)and learning together(4.95%)had a higher infection rate(χ^(2)=3135.58,P<0.001),and the interval between the last exposure and the onset of the index case was≤2 days(2.08%),and the infection rate was higher(χ^(2)=165.01,P<0.001),the index cases which were confirmed cases(5.49%)had a higher infection rate(χ^(2)=411.32,P<0.001).Multivariate Logistic regression analysis showed that Living together(OR:153.04,95%CI:70.64-331.56),eating together(OR:28.06,95%CI:12.36-63.73),learning together(OR:14.79,95%CI:6.69-32.68),and working together(OR:12.35,95%CI:5.27-28.96)and index cases were confirmed cases(OR:2.65,95%CI:2.11-3.33)with a high risk of infection.In the age group 21-40 years old(OR:0.64,95%CI:0.46-0.89),age group 41-60 years old(OR:0.56,95%CI:0.42-0.76)and the interval between the last exposure and the onset of the index case was≥3 days(OR:0.68,95%CI:0.54-0.84)had lower infection risk.Conclusions Age,contact method,last exposure time interval with index case,and classification of index cases are all influencing factors of infection among close contacts.The infection rate of co-living,dining together and learning in the same space is higher,and the accuracy of close contacts should be strengthened.Accurate judgment and classification management are of great significance to improving the effect of epidemic prevention and control.