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摘要:
目的 以广东省广州市、江苏省南京市、河南省郑州市3次Delta变异株引起的疫情为例,探索新型冠状病毒的不同传播模式,为科学防控提供依据。 方法 研究数据来源于国家及地方卫生健康委员会报告的广州、南京、郑州市相关疫情病例数据。 以行政地级市为单位,根据病例人口流动特点将传播模式分为跳跃传播和社区传播,比较两种传播模式的主要特征。 结果 2021年5月21日至9月3日,3次疫情共报告1 494例感染者,跳跃传播模式感染者83例,社区传播模式感染者1 411例,其中包含由跳跃传播导致的感染者884例。 跳跃传播共波及45个城市,传播时间为22 d,感染人群平均年龄为37.15岁,无症状者占26.51%;社区传播持续时间65 d,感染人群平均年龄为45.21岁,无症状者占8.65%;跳跃传播感染人群年龄低于跳跃传播,无症状者占比高于跳跃传播,差异均有统计学意义(P<0.001)。 结论 人口流动引发的跳跃传播涉及范围广,以年轻人为主,无症状感染者居多,社区传播以中老年人为主。 提示对不同人群可采取差异化管控,如对流动人群和交通枢纽岗位的人群加强核酸检测频次,对社区人群减少聚集性活动,降低接触频率可降低感染概率。 Abstract:Objective Taking the three outbreaks caused by Delta variant (B.1.617.2) in Guangzhou, Guangdong Province, Nanjing, Jiangsu Province and Zhengzhou, Henan Province as examples, to explore different transmission pattern of SARS-CoV-2 epidemic and to provide basis for scientific prevention and control. Methods The research data was collected from the public data based on three related epidemics in Guangzhou, Nanjing and Zhengzhou reported by the national and local health commissions. Taking prefecture level city as the unit, according to the characteristics of infected cases movement, the epidemic transmission pattern was divided into jumping transmission and community transmission, and compared the two patterns of its characteristics. Results From May 21 to September 3, 2021, 1 494 infected cases were reported in the three epidemics, including 83 cases of jumping transmission infections and 1 411 cases of community transmission infections including 884 infected cases caused by jumping transmission. Jumping transmission spread to a total of 45 cities for 22 days. The average age of the infected population was 37.15 years old, and the proportion of asymptomatic was 26.51%. The duration of community transmission was 65 days, and the average age of the infected population was 45.21 years old, the proportion of asymptomatic in which was 8.65%. The age of infected population was lower than that of jumping transmission, the proportion of asymptomatic was higher, and these differences were significant (P<0.001). Conclusion The jumping transmission caused by population movement covered a wide range, with high proportion of young person and asymptomatic infected cases. Infections of community transmission were mainly middle-aged and elderly people. Therefore, it is suggested that differentiated control should be taken for different groups, such as strengthening the frequency of nucleic acid testing for mobile people and people in transportation hub, reducing gathering activities for community groups that reducing the frequency of contact can reduce the probability of infection. -
Key words:
- SARS-CoV-2 /
- Transmission pattern /
- Epidemiological characteristics
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表 1 三次疫情中跳跃传播模式和社区传播模式比较
Table 1. Comparison of jumping transmission pattern and community transmission pattern in the three epidemics
变量 跳跃传播
(n=83)社区传播
(n=1 411)合计
(n=1 494)感染数(例)a 广州 3(3.62) 164(11.62) 167(11.18) 南京 71(85.54) 1 088(77.11) 1 159(77.64) 郑州 9(10.84) 159(11.27) 168(11.18) 传播时长(d) 广州 3 28 28 南京 19 37 37 郑州 7 24 24 传播速度(例/d) 广州 1.00 5.86 5.96 南京 3.73 29.41 31.32 郑州 1.29 6.62 7.00 注:a. 括号外数据为病例数(例),括号内数据为构成比(%) 表 2 不同传播模式下感染者流行病学特征
Table 2. Epidemiological characteristics of infections in different transmission patterns
组别 跳跃传播
(n=83)社区传播 总计
(n =1 494)首例报告市市内社区传播
(n =527)跳跃传播导致其他市社区传播
(n =884)合计
(n =1 411)年龄组(岁)a <20 11(17.74) 69(13.14) 132(16.26) 201(15.03) 212(15.15) 20~ 24(38.71) 121(23.05) 200(24.63) 321(24.01) 345(24.66) 40~ 21(33.87) 221(42.10) 225(27.71) 446(33.36) 467(33.38) ≥60 6(9.68) 114(21.71) 255(31.40) 369(27.60) 375(26.81) 性别a 男性 42(56.00) 226(42.97) 404(47.14) 630(45.55) 672(46.09) 女性 33(44.00) 300(57.03) 453(52.86) 753(54.45) 786(53.91) 初诊时有症状 是 48(57.83) 352(66.79) 705(79.75) 1 057(74.91) 1 105(73.96) 否 35(42.17) 175(33.21) 179(20.25) 354(25.09) 389(26.04) 病例类型 确诊病例 61(73.49) 485(92.03) 804(90.95) 1 289(91.35) 1 350(90.36) 无症状感染 22(26.51) 42(7.97) 80(9.05) 122(8.65) 144(9.64) 注:括号外数据为病例数,括号内数据为构成比(%);a. 存在缺失值 -
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