Department of Laboratory Medicine, Clinique St-Luc Bouge, Namur, Belgium; Department of Pharmacy, Namur Research Institute for LIfe Sciences, University of Namur, Belgium.
Department of Laboratory Medicine, Clinique St-Pierre, Ottignies, Belgium.
Clin Microbiol Infect. 2021 Sep;27(9):1351.e5-1351.e7. doi: 10.1016/j.cmi.2021.05.004. Epub 2021 May 8.
Data on the immune response after two doses of BNT162b2 are so far limited. Previously infected individuals were excluded from pivotal clinical trials and the optimum dose regimen in this population has not been clearly studied. The CRO-VAX HCP study aims to investigate the early antibody response in a population of health-care professionals having received two doses of the BNT162b2 mRNA coronavirus disease 2019 (COVID-19) vaccine.
The CRO-VAX HCP study is a multicentre, prospective, interventional study conducted in several sites in Belgium. The study included 231 health-care professional volunteers who received the two-dose regimen of the BNT162b2 mRNA COVID-19 vaccine. Of these, 73 were previously infected by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and 158 were uninfected and seronegative. In the first group, blood samples were collected at baseline and after 2, 4, 7, 10, 14, 21 and 28 days. In the second group, samples were obtained at baseline and after 14 and 28 days. Antibodies against the SARS-CoV-2 nucleocapsid and the receptor binding domain of the S1 subunit of the spike protein were measured in all individuals at different time-points.
In uninfected individuals, 95.5% (95% CI 91.0%-98.2%) developed anti-spike antibodies after 14 days and a 24.9-fold rise (95% CI 21.4%-28.9%) in antibody titre was observed after the second dose. In previously infected individuals, peak antibody response was reached after 7 days (i.e. 6347 U/mL) and the second dose did not lead to significantly higher antibody titres (i.e. 8856-11 911 U/mL). Antibody titres were higher in previously infected individuals.
This study supports the concept that a single dose of BNT162b2 would be sufficient in previously infected individuals.
目前关于 BNT162b2 接种两剂后的免疫反应数据有限。先前感染的个体被排除在关键临床试验之外，并且该人群中的最佳剂量方案尚未得到明确研究。CRO-VAX HCP 研究旨在调查已接种两剂 BNT162b2 mRNA 冠状病毒病 2019（COVID-19）疫苗的医护人员人群中的早期抗体反应。
CRO-VAX HCP 研究是一项多中心、前瞻性、干预性研究，在比利时的多个地点进行。该研究纳入了 231 名医护志愿者，他们接受了两剂 BNT162b2 mRNA COVID-19 疫苗的接种。其中，73 人曾被严重急性呼吸综合征冠状病毒 2（SARS-CoV-2）感染，158 人未感染且血清阴性。在第一组中，基线时和接种后第 2、4、7、10、14、21 和 28 天采集血样。在第二组中，在基线和接种后第 14 和 28 天采集血样。在不同时间点，所有个体均检测针对 SARS-CoV-2 核衣壳和 S1 亚单位刺突蛋白受体结合域的抗体。
在未感染个体中，95.5%（95%置信区间 91.0%-98.2%）在接种后 14 天产生抗刺突抗体，第二剂接种后抗体滴度升高 24.9 倍（95%置信区间 21.4%-28.9%）。在先前感染个体中，在第 7 天达到抗体反应峰值（即 6347 U/mL），第二剂接种不会导致抗体滴度显著升高（即 8856-11911 U/mL）。先前感染个体的抗体滴度更高。
本研究支持在先前感染个体中，一剂 BNT162b2 就足够的概念。
