新型冠状病毒疫苗对四川省部分地区新型冠状病毒奥密克戎变异株感染人群中的保护效果评价

Evaluation of the effectiveness of COVID-19 vaccines in people infected with omicron variant of COVID-19 in some areas of Sichuan Province

目的评价新型冠状病毒(简称新冠病毒)疫苗预防新冠病毒奥密克戎变异株感染所致发病、肺炎和重症的保护效果(Vaccine effectiveness,VE)。方法采用病例-病例研究,对2022年2至7月四川省成都市和广安市报告的新冠病毒感染本土病例进行调查,分析新冠病毒疫苗预防奥密克戎变异株发病、肺炎和重症的VE以及经年龄、性别、基础性疾病调整后的VE(aVE,Adjusted vaccine effectivenes),通过SPSS 21.0软件进行单因素和多因素Logistic回归分析,检验水准α=0.05。结果本研究共纳入新冠病毒感染病例1683例,均为新冠病毒奥密克戎变异株BA.2感染,临床结局为发病、肺炎和重症分别是511例(30.4%)、66例(3.9%)和11例(0.7%),重症人群中90.9%(10/11)都是60岁及以上老年人群。加强免疫预防奥密克戎变异株发病和肺炎的aVE分别是52.4%(95%CI:17.8%~72.4%)和81.6%(95%CI:60.0%~91.5%),基础免疫预防肺炎的a VE是69.2%(95%CI:26.9%~87.0%),未完成全程免疫不能有效预防发病和肺炎。结论新冠病毒疫苗加强免疫能有效预防奥密克戎变异株BA.2引起的发病和肺炎,且加强免疫比基础免疫预防肺炎的保护效果更高,未完成全程免疫不能有效预防发病和肺炎。所有符合接种条件的人群应及时完成新冠病毒疫苗基础免疫和加强免疫,尤其是60岁及以上老年人群。

Objective To evaluate the vaccine effectiveness(VE) of COVID-19 vaccines against symptomatic disease,pneumonia and severe illness caused by Omicron variant of COVID-19.Methods A case-case study was conducted to investigate local cases of COVID-19 infection reported in Chengdu City and Guang’an City,Sichuan Province from February to July in 2022.VE of COVID-19 vaccines against symptomatic disease,pneumonia and severe illness caused by Omicron variant,and adjusted VE(aVE)for age,sex and comorbidities were estimated.SPSS 21.0 software was used for univariate and multivariate Logistic regression model analysis.And the test level wasα=0.05.Results A total of 1683 cases of COVID-19 infection were included in this study,all of which were infected by Omicron variant strain BA.2.The clinical outcomes were 511 cases(30.4%)of symptomatic disease,66 cases(3.9%)of pneumonia and 11 cases(0.7%)of severe illness.90.9%(10/11)of severe cases were aged over 60 years old.The aVE of booster immunization was 52.4%(95%confidence interval CI:17.8%-72.4%)against symptomatic disease,and 81.6%(95%CI:60.0%-91.5%)against pneumonia.The aVE of primary immunization was 69.2%(95%CI:26.9%-87.0%)against pneumonia.Incomplete immunization could not effectively prevent the symptomatic disease and pneumonia.Conclusions The booster immunization of COVID-19 vaccines was effective against the symptomatic disease and pneumonia caused by Omicron variant BA.2.The effectiveness of booster immunization was higher than that of primary immunization against pneumonia.The incomplete immunization was not effective against symptomatic disease and pneumonia.All eligible individuals should complete the primary immunization and the booster immunization of COVID-19 vaccines in a timely manner,especially those over 60 years old.