From Associação Obras Sociais Irmã Dulce and the Oswaldo Cruz Foundation, Bahia (E.D.M.), and Centro Paulista de Investigação Clinica, São Paulo (C.Z.) - both in Brazil; Vaccine Research and Development, Pfizer, Hurley, United Kingdom (N.K., S.L., G.K.); Vaccine Research and Development, Pfizer, Collegeville, PA (X.X., J.L.P., X.W.); Vaccine Research and Development, Pfizer (S.S.D.), and California Research Foundation (D.M.B.), San Diego, and Kaiser Permanente Vaccine Study Center, Oakland (N.P.K.) - all in California; Vaccine Research and Development, Pfizer, Pearl River, NY (A.G., K.K., K.A.S., D.C., C.L., P.R.D., W.C.G., K.U.J.); Clinical Neuroscience Solutions, Orlando (M.E.D.), and Jacksonville Center for Clinical Research, Jacksonville (M.J.K.) - both in Florida; Clinical Research Professionals, Chesterfield, MO (T.W.J.); Accellacare, Wilmington, NC (K.D.C.); Clinical Trials of Texas, San Antonio (D.S.D.), and North Texas Infectious Diseases Consultants, Dallas (M.B.); East-West Medical Research Institute, Honolulu (D.F.P.); Johns Hopkins Bloomberg School of Public Health, Baltimore (L.L.H.); Tiervlei Trial Centre, Karl Bremer Hospital, Cape Town, South Africa (H.N.); BioNTech, Mainz, Germany (Ö.T., E.L., U.Ş.); and Worldwide Safety, Safety Surveillance and Risk Management, Pfizer, Groton, CT (D.B.T.).
N Engl J Med. 2022 May 19;386(20):1910-1921. doi: 10.1056/NEJMoa2200674. Epub 2022 Mar 23.
Active immunization with the BNT162b2 vaccine (Pfizer-BioNTech) has been a critical mitigation tool against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection during the coronavirus disease 2019 (Covid-19) pandemic. In light of reports of waning protection occurring 6 months after the primary two-dose vaccine series, data are needed on the safety and efficacy of offering a third (booster) dose in persons 16 years of age or older.
In this ongoing, placebo-controlled, randomized, phase 3 trial, we assigned participants who had received two 30-μg doses of the BNT162b2 vaccine at least 6 months earlier to be injected with a third dose of the BNT162b2 vaccine or with placebo. We assessed vaccine safety and efficacy against Covid-19 starting 7 days after the third dose.
A total of 5081 participants received a third BNT162b2 dose and 5044 received placebo. The median interval between dose 2 and dose 3 was 10.8 months in the vaccine group and 10.7 months in the placebo group; the median follow-up was 2.5 months. Local and systemic reactogenicity events from the third dose were generally of low grade. No new safety signals were identified, and no cases of myocarditis or pericarditis were reported. Among the participants without evidence of previous SARS-CoV-2 infection who could be evaluated, Covid-19 with onset at least 7 days after dose 3 was observed in 6 participants in the vaccine group and in 123 participants in the placebo group, which corresponded to a relative vaccine efficacy of 95.3% (95% confidence interval, 89.5 to 98.3).
A third dose of the BNT162b2 vaccine administered a median of 10.8 months after the second dose provided 95.3% efficacy against Covid-19 as compared with two doses of the BNT162b2 vaccine during a median follow-up of 2.5 months. (Funded by BioNTech and Pfizer; C4591031 ClinicalTrials.gov number, NCT04955626.).
接种 BNT162b2 疫苗（辉瑞-生物技术）进行主动免疫是 2019 年冠状病毒病（COVID-19）大流行期间对抗严重急性呼吸系统综合征冠状病毒 2（SARS-CoV-2）感染的关键缓解手段。鉴于有报告称在两剂初级疫苗系列接种后 6 个月保护作用减弱，需要了解 16 岁及以上人群接种第三剂（加强针）疫苗的安全性和有效性。
在这项正在进行的、安慰剂对照、随机、3 期试验中，我们将至少在 6 个月前接受两剂 30μg BNT162b2 疫苗的参与者分配接受第三剂 BNT162b2 疫苗或安慰剂注射。我们在第三剂接种后 7 天开始评估 COVID-19 的疫苗安全性和有效性。
共有 5081 名参与者接种了第三剂 BNT162b2，5044 名参与者接种了安慰剂。疫苗组第 2 剂和第 3 剂之间的中位间隔为 10.8 个月，安慰剂组为 10.7 个月；中位随访时间为 2.5 个月。第三剂的局部和全身不良反应事件通常为低级别。未发现新的安全性信号，也未报告心肌炎或心包炎病例。在可评估的无先前 SARS-CoV-2 感染证据的参与者中，疫苗组有 6 例 COVID-19 病例在第 3 剂接种后至少 7 天发病，安慰剂组有 123 例，疫苗相对有效性为 95.3%（95%置信区间，89.5 至 98.3）。
在第二次接种后中位数 10.8 个月接种第三剂 BNT162b2 疫苗，与两次 BNT162b2 疫苗接种相比，在中位数 2.5 个月的随访期间，对 COVID-19 的有效性为 95.3%。（由 BioNTech 和辉瑞资助；C4591031 临床试验.gov 编号，NCT04955626。）
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