Objective To describe the incidence of, risk factors for, and impact of vaccines on primary SARS-CoV-2 infection during the second wave of the covid-19 pandemic in susceptible hospital healthcare workers in England. Design Multicentre prospective cohort study. Setting National Health Service secondary care health organisations (trusts) in England between 1 September 2020 and 30 April 2021. Participants Clinical, support, and administrative staff enrolled in the SARS-CoV-2 Immunity and Reinfection Evaluation (SIREN) study with no evidence of previous infection. Vaccination status was obtained from national covid-19 vaccination registries and self-reported. Main outcome measure SARS-CoV-2 infection confirmed by polymerase chain reaction. Mixed effects logistic regression was conducted to determine demographic and occupational risk factors for infection, and an individual based mathematical model was used to predict how large the burden could have been if vaccines had not been available from 8 December 2020 . Results During England’s second wave, 12.9% (2353/18 284) of susceptible SIREN participants became infected with SARS-CoV-2. Infections peaked in late December 2020 and decreased from January 2021, concurrent with the cohort’s rapid vaccination coverage and a national lockdown. In multivariable analysis, factors increasing the likelihood of infection in the second wave were being under 25 years old (20.3% (132/651); adjusted odds ratio 1.35, 95% confidence interval 1.07 to 1.69), living in a large household (15.8% (282/1781); 1.54, 1.23 to 1.94, for participants from households of five or more people), having frequent exposure to patients with covid-19 (19.2% (723/3762); 1.79, 1.56 to 2.06, for participants with exposure every shift), working in an emergency department or inpatient ward setting (20.8% (386/1855); 1.76, 1.45 to 2.14), and being a healthcare assistant (18.1% (267/1479); 1.43, 1.16 to 1.77). Time to first vaccination emerged as being strongly associated with infection (P<0.001), with each additional day multiplying a participant’s adjusted odds ratio by 1.02. Mathematical model simulations indicated that an additional 9.9% of all patient facing hospital healthcare workers would have been infected were it not for the rapid vaccination coverage. Conclusions The rapid covid-19 vaccine rollout from December 2020 averted infection in a large proportion of hospital healthcare workers in England: without vaccines, second wave infections could have been 69% higher. With booster vaccinations being needed for adequate protection from the omicron variant, and perhaps the need for further boosters for future variants, ensuring equitable delivery to healthcare workers is essential. The findings also highlight occupational risk factors that persisted in healthcare workers despite vaccine rollout; a greater understanding of the transmission dynamics responsible for these is needed to help to optimise the infection prevention and control policies that protect healthcare workers from infection and therefore to support staffing levels and maintain healthcare provision. Trial registration ISRCTN registry [ISRCTN11041050][1]. The metadata for this analysis will be available on reasonable request to researchers through the Health Data Research UK CO-CONNECT platform and available for secondary analysis. [1]: /external-ref?link_type=ISRCTN&access_num=ISRCTN11041050

中文翻译：

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英格兰第二波期间医护人员感染 SARS-CoV-2 的负担和疫苗的影响：前瞻性多中心队列研究 (SIREN) 和数学模型

目的 描述在第二波 covid-19 大流行期间英国易感医院医护人员中疫苗对原发性 SARS-CoV-2 感染的发生率、危险因素和影响。设计多中心前瞻性队列研究。2020 年 9 月 1 日至 2021 年 4 月 30 日期间，在英国设立国家卫生服务二级保健卫生组织（信托）。参与者临床、支持和行政人员参加了 SARS-CoV-2 免疫和再感染评估 (SIREN) 研究，没有证据表明以前的感染。疫苗接种状况是从国家 covid-19 疫苗接种登记处获得的，并自行报告。主要结果衡量通过聚合酶链反应确认的 SARS-CoV-2 感染。进行混合效应逻辑回归以确定感染的人口和职业风险因素，并使用基于个体的数学模型来预测如果从 2020 年 12 月 8 日起没有疫苗，负担可能有多大。结果 在英格兰的第二波浪潮中，12.9% (2353/18 284) 的易感 SIREN 参与者感染了 SARS-CoV-2。感染在 2020 年 12 月下旬达到顶峰，并从 2021 年 1 月开始下降，与此同时该队列的疫苗接种覆盖率迅速提高，全国实行封锁。在多变量分析中，增加第二波感染可能性的因素是 25 岁以下（20.3%（132/651）；调整后的比值比 1.35，95% 置信区间 1.07 至 1.69），住在大家庭中（15.8 % (282/1781); 1.54, 1.23 至 1.94, 对于来自五人或五人以上家庭的参与者），经常接触 covid-19 患者（19.2% (723/3762)；1.79、1.56 至 2.06，对于每班都有接触的参与者），在急诊室或住院部工作病房设置 (20.8% (386/1855)；1.76，1.45 至 2.14)，以及担任医疗助理 (18.1% (267/1479)；1.43，1.16 至 1.77)。首次接种疫苗的时间与感染密切相关 (P<0.001)，每增加一天，参与者的调整后优势比就会乘以 1.02。数学模型模拟表明，如果不是快速的疫苗接种覆盖率，所有面对患者的医院医护人员中会有额外 9.9% 的人被感染。结论 从 2020 年 12 月开始快速推出 covid-19 疫苗避免了英格兰大部分医院医护人员的感染：如果没有疫苗，第二波感染率可能会高出 69%。由于需要加强疫苗接种以充分保护免受 omicron 变种的侵害，并且可能需要为未来的变种提供进一步的加强疫苗，因此确保公平地向医护人员提供疫苗至关重要。调查结果还强调了尽管疫苗推出，但医护人员仍然存在的职业风险因素；需要更好地了解造成这些问题的传播动态，以帮助优化感染预防和控制政策，保护医护人员免受感染，从而支持人员配置水平和维持医疗保健服务。试用注册 ISRCTN 注册表 [ISRCTN11041050][1]。该分析的元数据将根据合理要求通过英国健康数据研究 CO-CONNECT 平台提供给研究人员，并可用于二次分析。[1]: /external-ref?link_type=ISRCTN&access_num=ISRCTN11041050