新型冠状病毒奥密克戎BA2变异株感染者的临床特征及预后分析

Clinical characteristics of COVID-19 patients with Omicron BA.2 variant and their prognosis

目的分析新型冠状病毒奥密克戎BA2变异株感染者的临床特征及预后。方法本研究为回顾性观察性研究。采用非随机抽样方法收集2022年4月3日至28日在上海市奉贤区青高路集中隔离收治点进行隔离或治疗且资料完整的969例新型冠状病毒感染无症状及轻型患者的临床资料和核酸检测结果, 及解除隔离之后的1个月随访期数据。对性别、年龄、疫苗接种史、基础疾病史、临床症状表现及复阳情况等进行统计比较, 并将年龄、收治初始及过程中核酸Ct值、疫苗接种剂次及接种时间等因素与临床特征及预后的相关性进行多因素统计分析。结果共纳入969例新型冠状病毒感染者, 其中无症状感染者410例(42.3%), 轻型患者559例(57.7%);男549例(56.7%), 女420例(43.3%);年龄(40.51±17.43)岁。轻型患者的主要症状为咳嗽、咽喉痛、鼻塞、发热、流涕。所有入组者核酸检测初始N基因Ct(NCt)值为(28.64±7.96), ORF1ab基因Ct(ORF1abCt)值为(31.91±7.35)。所有入组者解除集中隔离观察的时间为(17.67±3.95)d。无症状感染者ORF1abCt均值、NCt均值、初始ORF1abCt值、初始NCt值均高于轻型患者, 差异均有统计学意义(均P<0.05)。接种新型冠状病毒疫苗者855例(88.2%), 其中接种3剂疫苗者489例(50.5%);距离末次接种时间为90 d内的感染者为49例(5.1%), 超过90 d的感染者为440例(45.4%);距离末次接种时间为90 d内感染者的NCt和ORF1abCt值均高于超过90 d的感染者, 差异均有统计学意义(均P<0.05)。随着ORF1abCt均值的升高, 核酸转双阴时间缩短(P<0.01);随着年龄的升高, 核酸转双阴时间延长(P<0.01)。解除隔离后1个月内随访记录到19例复阳感染者, 解除隔离距离复阳的时间为(10.16±3.45)d。19例复阳患者均表现为无症状感染者。结论无症状感染者的病毒载量低于轻型患者;60岁以上老年人症状少, 但核酸转阴时间长;接种3剂疫苗且距离接种时间90 d以内的感染者的病毒载量更低。

Objective To analyze the clinical characteristics of COVID-19 patients with Omicron BA.2 variant and their prognosis.Methods It was a retrospective study involving 969 asymptomatic and mild COVID-19 patients treated in a centralized isolation and admission site in Qinggao Road,Fengxian District,Shanghai from 3rd April 2022 to 28th April 2022 were randomly recruited.Their clinical data,nucleic testing data and follow-up data within 1 month of isolation were analyzed.The sex,age,vaccination history,history of basic diseases,clinical symptoms and recovery status were recorded.Multivariate logistic regression analysis was performed to identify the correlation between the age,nucleic acid Ct values on admission and during the treatment,vaccination doses and vaccination time with the clinical characteristics and prognosis of COVID-19 patients.Results A total of 969 COVID-19 patients,including 410 asymptomatic cases(42.3%)and 559 mild cases(57.7%),were enrolled.There were 549(56.7%)males and 420(43.3%)females,with an average age of(40.51±17.43)years.The main symptoms of COVID-19 patients with mild symptoms were cough,sore throat,stuffy nose,fever,and runny nose.The mean Ct values of the N gene(NCt)and ORF1ab gene(ORF1ab Ct)of all participants were 28.64±7.96 and 31.91±7.35,respectively,and the time from admission to discharge from the centralized isolation and admission site was(17.67±3.950)days.The mean value of NCt and ORF1ab Ct,and the initial value of NCt and ORF1ab Ct in asymptomatic infected patients were significantly higher than those in COVID-19 patients with mild symptoms(P<0.05).A total of 855 cases(88.2%)received COVID-19 vaccines,including 489 cases(50.5%)receiving 3 doses.In total,49(5.1%)cases were infected within 90 days from the last vaccination,and 440(45.4%)cases were infected over 90 days.The mean value of NCt and ORF1ab Ct in individuals infected within 90 days was significantly higher than that in individuals infected over 90 days(P<0.05).As the mean ORFlabCt increased,the time from admission to a double negative test was significantly reduced(P<0.01),which significantly prolonged with aging(P<0.01).After discharge from the centralized isolation site nineteen patients who were followed up were infected again within 1 month.The average time from discharge to the second infection was(10.16±3.45)days.All the 19 patients who were re-infected were asymptomatic.Conclusions The viral load of asymptomatically infected individuals is lower than that of COVID-19 patients with mild symptoms.Elderly people over 60 years have fewer symptoms,but to take longer time to turn negative.Individuals who have received all 3 doses of vaccines and those infected within 90 days from last vaccination have a lower viral load.