论文部分内容阅读
目的:了解北京市境外输入性新型冠状病毒肺炎病例在京密切接触者的流行病学特征，为评估和优化境外输入性新型冠状病毒肺炎疫情防控措施提供科学依据。方法:使用密切接触者调查表，调查北京市2020年2月至4月期间报告的境外输入性病例在京密切接触者基本信息、暴露相关信息等。在密切接触者纳入隔离医学观察后，追踪每日健康监测状况，描述其流行病学特征、转归情况，计算不同类型、不同暴露条件和不同隔离医学观察方式下，密切接触者转为确诊病例的感染率。结果:北京市境外输入性新型冠状病毒肺炎病例及密切接触者的变化趋势均大致呈钟型曲线。截至2020年4月30日，累计对1 271例境外输入性新型冠状病毒肺炎病例在京密切接触者完成了隔离医学观察，转归情况分别为期满解除1 245例、确诊26例、无症状感染0例，总感染率为2.05%；其中航班密接感染率0.69%（7/1 011），非航班密接感染率7.31%（19/260）。暴露类型为同餐（37.50%）、同住（30.23%），曾经出现症状（34.62%），非航班密切接触者（7.31%），隔离观察方式为住院（68.97%），与确诊病例同排（2.07%）及机组人员（16.67%）的密切接触者感染率较高。结论:北京市境外输入性新型冠状病毒肺炎病例在京密切接触者以航班密切接触为主，航班密切接触者转为确诊病例的感染率低，应继续坚持并优化各项科学措施，严格防控境外输入疫情。暴露类型、与病例座位相距排数等因素可能是密切接触者转归的影响因素。“,”Objective:To understand epidemiological characteristics of close contacts of imported coronavirus disease 2019 (COVID-19) cases reported in Beijing, so as to provide scientific basis for the evaluation and optimization of the prevention and control measures of imported COVID-19 cases.Methods:The close contact questionnaire was used to investigate the basic information and exposure information of the imported cases from February to April, 2020 in Beijing to track the daily health status after close contacts were placed under medical observation in isolation, and to describe its epidemiological characteristics and prognosis. The infection rate of the close contacts converted to confirmed cases under different types, different exposure conditions and different isolation medical observation methods were calculated.Results:The variation trend of the imported COVID-19 cases from other countries and the close contacts in Beijing showed a roughly bell-shaped curve. By the end of 3April 30, 2020, a total of 1 271 close contacts of imported COVID-19 cases from other countries had completed the medical observation in Beijing. At the end of the period, 1 245 cases were discharged, 26 cases were diagnosed as confirmed cases and 0 cases of asymptomatic case. The overall infection rate was 2.05%. The infection rates of close contacts on flights and not-on-flight were 0.69% (7/1011) and 7.31% (19/260), respectively. The infection rates of the close contacts with exposure types of dining together (37.50%), living in the same room (30.23%), ever being symptomatic (34.62%), not-on-flight closely contacting (7.31%), quarantine by hospitalization (68.97%), sitting in the same row with confirmed case on the flight (2.07%) and flight crews (16.67%) were relatively high.Conclusions:Close contacts of imported COVID-19 cases from abroad in Beijing were mainly exposed on flights. The rate of conversion from on-flight close contacts to confirmed cases was low. There was a need to persist and optimize all scientific measures for strictly prevent and control of imported COVID-19 cases from abroad. The type of exposure and the number of rows away from the seats of the patients may be the factors affecting the outcome of close contacts.