摘要
目的 分析比较宁波市Delta和Omicron变异株引发本土聚集性疫情续发感染者的流行特征,为进一步优化调整新冠肺炎疫情的防控措施提供参考依据。方法 以2021年12月1日-2022年5月31日宁波市37起本土新冠肺炎疫情中判定为密切接触者(密接)中的171例续发感染者为研究对象,对两种变异株的感染者流行特征进行描述性分析,以与关联病例有明确暴露时间的续发感染者计算潜伏期。结果 确诊病例占80.70%(138/171),无症状感染者占19.30%(33/171)。Delta和Omicron变异株感染者分别占64.33%(110/171)和35.67%(61/171),Omicron变异株的无症状感染者比例高于Delta变异株(54.1%vs. 0,P <0.01)。与关联病例有明确暴露时间的22例确诊病例(Delta变异株15例,Omicron变异株7例)平均潜伏期为(3.45±0.44)d,Delta和Omicron变异株感染者的最长潜伏期分别为8和6 d,平均潜伏期分别为(3.60±0.58)和(3.14±0.63)d,差异无统计学意义(P> 0.05)。Omicron变异株感染者末次暴露至核酸检测首次阳性间隔时间均≤7d。Omicron变异株感染者核酸检测首次阳性N基因Ct值高于Delta变异株感染者,但平均住院天数少于Delta变异株(P均<0.05)。结论 Omicron变异株引发本地疫情的潜伏期<7 d且较Delta变异株的致病性低,建议调整密接的管控措施为7 d集中隔离和3 d居家健康监测。
Objective To analyze and compare prevalence characteristics of coronavirus disease 2019(COVID-19)cluster epidemic-related secondary infections caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)Delta and Omicron variant in Ningbo city, and to provide a basis for optimizing and adjusting measures on COVID-19prevention and control. Methods From the National Information System for Disease Control and Prevention and the reports of field surveys, we extracted the information on 171 COVID-19 cases with SARS-CoV-2 Delta and Omicron variant infection identified among close contacts of 37 local COVID-19 outbreaks in Ningbo city from December 1, 2021 to May 31,2022. Descriptive analysis was performed to analyze prevalence characteristics of the cases and the incubation period of secondary infection was calculated for the cases with definite exposure time to index cases. Results Of all the cases, 80.70%(n = 138) and 19.30%(n = 33) were confirmed patients and asymptomatic infections;64.33%(n = 110) and 35.67%(n = 61)were infected with SARS-CoV-2 Delta and Omicron variant, respectively. The proportion of asymptomatic infection was significantly higher in the cases infected with Omicron variant than that in the cases with Delta variant(54.10% vs. 0,P <0.05). The mean incubation period was 3.45 ± 0.44 days for the 22 confirmed cases(15 and 7 with Delta and Omicron variant infection) after a definite exposure to the index case. The longest incubation period of Delta and Omicron variant infection were 8 and 6 days. The mean incubation period was 3.60 ± 0.58 and 3.14 ± 0.63 days for Delta and Omicron variant infection, with no significant difference(P > 0.05). The interval time between the last exposure and the first positive detection of nucleic acid was ≤ 7 days for the cases with Omicron variant infection. The Ct value of N gene at the first positive nucleic acid detection was significantly higher in the patients with Omicron variant infection than that in those with Delta variant infection(P < 0.05), but
作者
褚衍茹
张栋梁
陈奕
易波
雷松
张言武
劳旭影
顾晓敏
王海波
丁克琴
许国章
CHU Yan-ru;ZHANG Dong-liang;CHEN Yi(Ningbo Municipal Centre for Disease Control and Prevention,Ningbo,Zhejiang Province 315010,China)
出处
《中国公共卫生》
CAS
CSCD
北大核心
2022年第9期1170-1174,共5页
Chinese Journal of Public Health
基金
宁波市“科技创新2025”重大专项(2021Z021)
宁波市医疗卫生品牌学科(PPXK2018–10)
宁波市应急科技攻关重大专项(2022Z034)
国家自然科学基金(82073514)。
