World Health Organization Regional Office for Europe, Copenhagen, Denmark.
Epiconcept, Paris, France.
PLoS One. 2024 Sep 6;19(9):e0307805. doi: 10.1371/journal.pone.0307805. eCollection 2024.
Healthcare workers (HCWs) have suffered considerable morbidity and mortality during the COVID-19 pandemic. Few data on COVID-19 vaccine effectiveness (VE) are available from middle-income countries in the WHO European Region. We evaluated primary series COVID-19 VE against laboratory-confirmed COVID-19 among HCWs in Georgia.
HCWs in six hospitals in Georgia were invited to enroll in a prospective cohort study conducted during March 19-December 5, 2021. Participants completed weekly symptom questionnaires. Symptomatic HCWs were tested by RT-PCR and/or rapid antigen test (RAT), and participants were routinely tested for SARS-CoV-2 by RT-PCR or RAT, regardless of symptoms. Serology was collected at enrolment, and quarterly thereafter, and tested by electrochemiluminescence immunoassay for SARS-CoV-2 antibodies. We defined primary series vaccination as two doses of COVID-19 vaccine received ≥14 days before symptom onset. We estimated VE as (1-hazard ratio)*100 using a Cox proportional hazards model with vaccination status as a time-varying covariate. Estimates were adjusted by potential confounders that changed the VE estimate by more than 5%, according to the change-in-estimate approach.
Overall, 1561/3849 (41%) eligible HCWs enrolled and were included in the analysis. The median age was 40 (IQR: 30-53), 1318 (84%) were female, and 1003 (64%) had laboratory evidence of prior SARS-Cov-2 infection. At enrolment, 1300 (83%) were unvaccinated; By study end, 1082 (62%) had completed a primary vaccine series (69% BNT162b2 (Pfizer-BioNTech); 22% BBIBP-CorV (Sinopharm); 9% other). During the study period, 191(12%) participants had a new PCR- or RAT-confirmed symptomatic SARS-CoV-2 infection. VE against PCR- or RAT- confirmed symptomatic SARS-CoV-2 infection was 58% (95%CI: 41; 70) for all primary series vaccinations, 68% (95%CI: 51; 79) for BNT162b2, and 40% (95%CI: 1; 64) for BBIBP-CorV vaccines. Among previously infected HCWs, VE was 58% (95%CI: 11; 80). VE against medically attended COVID-19 was 52% (95%CI: 28; 68), and VE against hospitalization was 69% (95% CI: 36; 85). During the period of predominant Delta variant circulation (July-December 2021), VE against symptomatic COVID-19 was 52% (95%CI: 30; 66).
Primary series vaccination with BNT162b2 and BBIBP-CorV was effective at preventing COVID-19 among HCWs, most of whom had previous infection, during a period of mainly Delta circulation. Our results support the utility of COVID-19 primary vaccine series, and the importance of increasing coverage, even among previously infected individuals.
在 COVID-19 大流行期间，医护人员（HCWs）遭受了相当大的发病率和死亡率。世界卫生组织欧洲区域的中等收入国家提供的 COVID-19 疫苗有效性（VE）数据很少。我们评估了格鲁吉亚 HCWs 初级系列 COVID-19 对实验室确诊 COVID-19 的 VE。
格鲁吉亚的六家医院邀请 HCWs 参加 2021 年 3 月 19 日至 12 月 5 日期间进行的前瞻性队列研究。参与者每周完成症状问卷。有症状的 HCWs 通过 RT-PCR 和/或快速抗原检测（RAT）进行检测，参与者定期通过 RT-PCR 或 RAT 检测 SARS-CoV-2，无论症状如何。在登记时和之后的每季度收集血清学，并通过电化学发光免疫测定法检测 SARS-CoV-2 抗体。我们将初级系列疫苗接种定义为在症状出现前 14 天内接受两剂 COVID-19 疫苗。我们使用 Cox 比例风险模型估计 VE，疫苗接种状态作为时间变化的协变量。根据变化估计方法，根据改变 VE 估计值超过 5%的潜在混杂因素调整估计值。
总体而言，1561/3849（41%）符合条件的 HCWs 登记并纳入分析。中位年龄为 40（IQR：30-53），1318 名（84%）为女性，1003 名（64%）有 SARS-Cov-2 感染的实验室证据。在登记时，1300 名（83%）未接种疫苗；研究结束时，1082 名（62%）完成了初级疫苗系列（69%BNT162b2（辉瑞-生物技术）；22% BBIBP-CorV（国药）；9%其他）。在研究期间，191 名（12%）参与者发生了新的 PCR 或 RAT 确诊的有症状 SARS-CoV-2 感染。针对所有初级系列疫苗接种的 PCR 或 RAT 确诊有症状 SARS-CoV-2 感染的 VE 为 58%（95%CI：41；70），BNT162b2 为 68%（95%CI：51；79），BBIBP-CorV 疫苗为 40%（95%CI：1；64）。在先前感染的 HCWs 中，VE 为 58%（95%CI：11；80）。针对有医疗记录的 COVID-19 的 VE 为 52%（95%CI：28；68），针对住院的 VE 为 69%（95% CI：36；85）。在 Delta 变体主要流行期间（2021 年 7 月至 12 月），针对有症状 COVID-19 的 VE 为 52%（95%CI：30；66）。
在 Delta 变体主要流行期间，BNT162b2 和 BBIBP-CorV 的初级系列疫苗接种在预防 HCWs 中的 COVID-19 方面是有效的，其中大多数人以前都感染过。我们的研究结果支持 COVID-19 初级疫苗系列的效用，以及提高覆盖率的重要性，即使在以前感染过的人群中也是如此。
