Hospital Israelita Albert Einstein, São Paulo, Brazil.
Department of Internal Medicine, University of Iowa, Iowa City, Iowa, USA.
Clin Infect Dis. 2023 Feb 8;76(3):e360-e366. doi: 10.1093/cid/ciac430.
Little is currently known about vaccine effectiveness (VE) for either 2 doses of Oxford-AstraZeneca (ChAdOx1) viral vector vaccine or CoronaVac (Instituto Butantan) inactivated viral vaccine followed by a third dose of mRNA vaccine (Pfizer/BioNTech) among healthcare workers (HCWs).
We conducted a retrospective cohort study among HCWs (aged ≥18 years) working in a private healthcare system in Brazil from January to December 2021. VE was defined as 1 - incidence rate ratio (IRR), with IRR determined using Poisson models with the occurrence of laboratory-confirmed coronavirus disease 2019 (COVID-19) infection as the outcome, adjusting for age, sex, and job type. We compared those receiving viral vector or inactivated viral primary series (2 doses) with those who received an mRNA booster.
A total of 11 427 HCWs met the inclusion criteria. COVID-19 was confirmed in 31.5% of HCWs receiving 2 doses of CoronaVac vaccine versus 0.9% of HCWs receiving 2 doses of CoronaVac vaccine with mRNA booster (P < .001) and 9.8% of HCWs receiving 2 doses of ChAdOx1 vaccine versus 1% among HCWs receiving 2 doses of ChAdOx1 vaccine with mRNA booster (P < .001). In the adjusted analyses, the estimated VE was 92.0% for 2 CoronaVac vaccines plus mRNA booster and 60.2% for 2 ChAdOx1 vaccines plus mRNA booster, when compared with those with no mRNA booster. Of 246 samples screened for mutations, 191 (77.6%) were Delta variants.
While 2 doses of ChAdOx1 or CoronaVac vaccines prevent COVID-19, the addition of a Pfizer/BioNTech booster provided significantly more protection.
目前对于在医护工作者（HCWs）中接种两剂牛津-阿斯利康（ChAdOx1）病毒载体疫苗或科兴（Instituto Butantan）灭活病毒疫苗，随后再接种第三剂 mRNA 疫苗（辉瑞/生物科技），两剂疫苗的有效性（VE）或第三剂疫苗的有效性知之甚少。
我们对巴西一家私营医疗系统中的 HCWs（年龄≥18 岁）进行了一项回顾性队列研究。2021 年 1 月至 12 月间，VE 被定义为 1-发病率比（IRR），采用泊松模型确定 IRR，将实验室确诊的 2019 年冠状病毒病（COVID-19）感染的发生作为结局，并对年龄、性别和工作类型进行调整。我们将接受病毒载体或灭活病毒初免系列（2 剂）的人群与接受 mRNA 加强针的人群进行了比较。
共有 11427 名 HCWs 符合纳入标准。接种两剂科兴疫苗的 HCWs 中 COVID-19 确诊率为 31.5%，而接种两剂科兴疫苗加 mRNA 加强针的 HCWs 中 COVID-19 确诊率为 0.9%（P<.001），接种两剂 ChAdOx1 疫苗的 HCWs 中 COVID-19 确诊率为 9.8%，而接种两剂 ChAdOx1 疫苗加 mRNA 加强针的 HCWs 中 COVID-19 确诊率为 1%（P<.001）。在调整分析中，与未接种 mRNA 加强针相比，两剂科兴疫苗加 mRNA 加强针的估计 VE 为 92.0%，两剂 ChAdOx1 疫苗加 mRNA 加强针的 VE 为 60.2%。在 246 份筛查突变的样本中，191 份（77.6%）为 Delta 变异株。
虽然两剂 ChAdOx1 或科兴疫苗可预防 COVID-19，但接种辉瑞/生物科技加强针可显著提高保护效力。
