Epidemiology Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan (Italy);
These authors equally contributed to this paper.
Epidemiol Prev. 2022 Jul-Aug;46(4):250-258. doi: 10.19191/EP22.4.A513.065.
to evaluate immunogenicity and effectiveness of BNT162b2 COVID-19 vaccine in a cohort of healthcare workers (HCWs).
cohort study.
in a hospital in Milan (Lombardy Region, Northern Italy) HCWs without ("negative cohort") and with ("positive cohort") history of SARS-CoV-2 infection or elevated serum antibody before the vaccination campaign (27.12.2020) were included. Data collection and follow-up covered the period 27.12.2020-13.05.2022.
5,596 HCWs were included, 4,771 in the negative and 825 in the positive cohort. In both cohorts, serum anti-S1 antibodies were high one months after the second dose, halved after six months, and returned to high levels after the third dose. In the negative cohort, 1,401 SARS-CoV-2 infections were identified. VE was 70% (95%CI 54-80; 46 infected) in the first four months after the second dose and later declined to 16% (95%CI 0-43; 97 infected). After the third dose, VE increased to 57% (95%CI 35-71; 61 infected) in the first month but rapidly declined over time, particularly after three months (24% in the fourth month and 1% afterwards). The number of infections avoided by vaccination was estimated to be 643 (95%CI 236-1,237).
in spite of rapidly declining effectiveness, vaccination helped to avoid several hundred infections in the considered hospital.
评估 BNT162b2 COVID-19 疫苗在医护人员（HCWs）队列中的免疫原性和有效性。
队列研究。
在米兰的一家医院（意大利北部伦巴第大区），纳入了在疫苗接种运动前（2020 年 12 月 27 日）没有（“阴性队列”）和有（“阳性队列”）SARS-CoV-2 感染史或血清抗体升高的 HCWs。数据收集和随访覆盖了 2020 年 12 月 27 日至 2022 年 5 月 13 日的时间段。
共纳入 5596 名 HCWs，其中 4771 名在阴性队列，825 名在阳性队列。在两个队列中，第二次接种后一个月血清抗-S1 抗体水平较高，六个月后减半，第三次接种后又恢复到高水平。在阴性队列中，共发现 1401 例 SARS-CoV-2 感染。第二次接种后四个月 VE 为 70%（95%CI 54-80；46 例感染），随后下降至 16%（95%CI 0-43；97 例感染）。第三次接种后，第一个月 VE 增加至 57%（95%CI 35-71；61 例感染），但随着时间的推移迅速下降，尤其是在三个月后（第四个月 24%，之后为 1%）。估计接种疫苗可避免 643 例（95%CI 236-1237）感染。
尽管有效性迅速下降，但疫苗接种仍有助于避免该医院发生数百例感染。
