BNT162b2 疫苗对 5 至 11 岁儿童中奥密克戎的有效性。
BNT162b2 Vaccine Effectiveness against Omicron in Children 5 to 11 Years of Age.
机构信息
From the Clalit Research Institute, Innovation Division (C.J.C.-S., O.M., R.D.B., N.D.), and the Community Medicine Division (S.Y., A.P., D.N.), Clalit Health Services, and the Faculty of Medicine, Tel-Aviv University (L.L.), Tel Aviv, the Research Authority, Rabin Medical Center, Petah-Tiqva (L.L.), the ARC (Accelerate Redesign Collaborate) Innovation Center, Chaim Sheba Medical Center at Tel HaShomer, Ramat-Gan (N.B.), Software and Information Systems Engineering (N.B., N.D.), and the School of Public Health (R.D.B.), Ben Gurion University of the Negev, Be'er Sheva, and the School of Public Health, University of Haifa, Haifa (A.P.) - all in Israel; the Departments of Biomedical Informatics (N.B., B.Y.R., N.D.) and Pediatrics (B.Y.R.), Harvard Medical School, CAUSALab, Departments of Epidemiology and Biostatistics (M.A.H.), and the Center for Communicable Disease Dynamics, Departments of Epidemiology and Immunology and Infectious Diseases (M.L.), Harvard T.H. Chan School of Public Health, the Ivan and Francesca Berkowitz Family Living Laboratory Collaboration, Harvard Medical School and Clalit Research Institute (B.Y.R., R.D.B., N.D.), and the Predictive Medicine Group, Computational Health Informatics Program, Boston Children's Hospital (B.Y.R.) - all in Boston; the Department of Women and Child Health, University of Padua, Padua, Italy (C.G.); and the Medical Research Council Clinical Trials Unit, University College London, London (A.J.).
出版信息
N Engl J Med. 2022 Jul 21;387(3):227-236. doi: 10.1056/NEJMoa2205011. Epub 2022 Jun 29.
BACKGROUND
Limited evidence is available on the real-world effectiveness of the BNT162b2 vaccine against coronavirus disease 2019 (Covid-19) and specifically against infection with the omicron variant among children 5 to 11 years of age.
METHODS
Using data from the largest health care organization in Israel, we identified a cohort of children 5 to 11 years of age who were vaccinated on or after November 23, 2021, and matched them with unvaccinated controls to estimate the vaccine effectiveness of BNT162b2 among newly vaccinated children during the omicron wave. Vaccine effectiveness against documented severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and symptomatic Covid-19 was estimated after the first and second vaccine doses. The cumulative incidence of each outcome in the two study groups through January 7, 2022, was estimated with the use of the Kaplan-Meier estimator, and vaccine effectiveness was calculated as 1 minus the risk ratio. Vaccine effectiveness was also estimated in age subgroups.
RESULTS
Among 136,127 eligible children who had been vaccinated during the study period, 94,728 were matched with unvaccinated controls. The estimated vaccine effectiveness against documented infection was 17% (95% confidence interval [CI], 7 to 25) at 14 to 27 days after the first dose and 51% (95% CI, 39 to 61) at 7 to 21 days after the second dose. The absolute risk difference between the study groups at days 7 to 21 after the second dose was 1905 events per 100,000 persons (95% CI, 1294 to 2440) for documented infection and 599 events per 100,000 persons (95% CI, 296 to 897) for symptomatic Covid-19. The estimated vaccine effectiveness against symptomatic Covid-19 was 18% (95% CI, -2 to 34) at 14 to 27 days after the first dose and 48% (95% CI, 29 to 63) at 7 to 21 days after the second dose. We observed a trend toward higher vaccine effectiveness in the youngest age group (5 or 6 years of age) than in the oldest age group (10 or 11 years of age).
CONCLUSIONS
Our findings suggest that as omicron was becoming the dominant variant, two doses of the BNT162b2 messenger RNA vaccine provided moderate protection against documented SARS-CoV-2 infection and symptomatic Covid-19 in children 5 to 11 years of age. (Funded by the European Union through the VERDI project and others.).
背景
关于 BNT162b2 疫苗在现实世界中针对 2019 年冠状病毒病（COVID-19）的有效性，特别是针对 5 至 11 岁儿童感染奥密克戎变异株的有效性，现有证据有限。
方法
利用以色列最大的医疗保健组织的数据，我们确定了一组 5 至 11 岁的儿童，他们于 2021 年 11 月 23 日或之后接种疫苗，并将其与未接种疫苗的对照进行匹配，以估计在奥密克戎浪潮期间新接种疫苗的儿童中 BNT162b2 的疫苗有效性。在接种第一剂和第二剂后，分别估计疫苗对新记录的严重急性呼吸系统综合征冠状病毒 2（SARS-CoV-2）感染和有症状 COVID-19 的有效性。通过使用 Kaplan-Meier 估计法，在 2022 年 1 月 7 日之前，对两组研究中的每个结果的累积发生率进行估计，疫苗有效性计算为 1 减去风险比。还按年龄亚组估计了疫苗的有效性。
结果
在研究期间接种疫苗的 136127 名符合条件的儿童中，有 94728 名与未接种疫苗的对照组相匹配。在接种第一剂后 14 至 27 天，接种疫苗对记录感染的有效性估计为 17%（95%置信区间[CI]，7 至 25），而在接种第二剂后 7 至 21 天，有效性估计为 51%（95%CI，39 至 61）。在接种第二剂后 7 至 21 天，研究组之间的绝对风险差异为每 100000 人中有 1905 例确诊感染（95%CI，1294 至 2440）和 599 例有症状 COVID-19（95%CI，296 至 897）。在接种第一剂后 14 至 27 天，接种疫苗对有症状 COVID-19 的有效性估计为 18%（95%CI，-2 至 34），而在接种第二剂后 7 至 21 天，有效性估计为 48%（95%CI，29 至 63）。我们观察到，在最年轻的年龄组（5 或 6 岁）中，疫苗的有效性高于最年长的年龄组（10 或 11 岁）。
结论
我们的研究结果表明，随着奥密克戎成为主要变异株，两剂 BNT162b2 信使 RNA 疫苗在 5 至 11 岁儿童中对新记录的 SARS-CoV-2 感染和有症状的 COVID-19 提供了中等程度的保护。（由欧盟通过 VERDI 项目和其他项目资助）。
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