Background The correlates of protection against SARS-CoV-2 and their longevity remain unclear. Studies in severely ill individuals have identified robust cellular and humoral immune responses against the virus. Asymptomatic infection with SARS-CoV-2 has also been described, but it is unknown whether this is sufficient to produce antibody responses. Methods We performed a cross-sectional study recruiting 554 health care workers from University Hospitals Birmingham NHS Foundation Trust who were at work and asymptomatic. Participants were tested for current infection with SARS-CoV-2 by nasopharyngeal swab for real-time polymerase chain reaction and for seroconversion by the measurement of anti-SARS-CoV-2 spike glycoprotein antibodies by enzyme linked immunosorbent assay. Results were interpreted in the context of previous, self-reported symptoms of illness consistent with COVID-19. Results The point prevalence of infection with SARS-CoV-2, determined by the detection of SARS-CoV-2 RNA on nasopharnygeal swab was 2.39% (n=13/544). Serum was available on 516 participants. The overall rate of seroconversion in the cohort was 24.4% (n=126/516). Individuals who had previously experienced a symptomatic illness consistent with COVID-19 had significantly greater seroconversion rates than those who had remained asymptomatic (37.5% vs 17.1%, χ2 =21.1034, p<0.0001). In the week preceding peak COVID-19-related mortality at UHBFT, seroconversion rates amongst those who were suffering from symptomatic illnesses peaked at 77.8%. Prior symptomatic illness generated quantitatively higher antibody responses than asymptomatic seroconversion. Seroconversion rates were highest amongst those working in housekeeping (34.5%), acute medicine (33.3%) and general internal medicine (30.3%) with lower rates observed in participants working in intensive care (14.8%) and emergency medicine (13.3%). Conclusions In a large cross-sectional seroprevalence study of health-care workers, we demonstrate that asymptomatic seroconversion occurs, however prior symptomatic illness is associated with quantitatively higher antibody responses. The identification that the potential for seroconversion in health-care workers can associate differentially with certain hospital departments may inform future infection control and occupational health practices.

中文翻译：

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医护人员的SARS-CoV-2血清转化

背景对抗SARS-CoV-2的保护及其寿命的相关性尚不清楚。对重症患者的研究已经确定了针对病毒的强大的细胞和体液免疫反应。也已经描述了SARS-CoV-2的无症状感染，但是尚不清楚这是否足以产生抗体反应。方法我们进行了一项横断面研究，招募了来自伯明翰大学医院NHS基金会信托基金的554名卫生保健工作者，他们工作且无症状。通过鼻咽拭子测试参与者当前感染SARS-CoV-2的实时聚合酶链反应和通过酶联免疫吸附测定法测量抗SARS-CoV-2穗状糖蛋白抗体的血清转化。结果是在先前的背景下进行解释的，自我报告的疾病症状与COVID-19一致。结果通过检测鼻咽拭子上的SARS-CoV-2 RNA可以确定SARS-CoV-2感染的点流行率为2.39％（n = 13/544）。516名参与者可获得血清。队列中血清转化的总率为24.4％（n = 126/516）。与没有症状的患者相比，先前经历过与COVID-19一致的症状性疾病的患者具有更高的血清转化率（37.5％比17.1％，χ2= 21.1034，p <0.0001）。在UHBFT与COVID-19相关的死亡率达到峰值之前的一周，患有症状性疾病的患者的血清转化率达到了77.8％的峰值。与无症状的血清转化相比，先前有症状的疾病在定量上产生更高的抗体反应。在从事家政工作的患者中，血清转化率最高（34.5％），在急诊科中占33.3％，在普通内科中占30.3％，在重症监护室（14.8％）和急诊科（13.3％）中，血清转化率较低。结论在一项针对卫生保健工作者的大型横断面血清流行病学研究中，我们证明了无症状的血清转化发生，但是先前有症状的疾病与定量更高的抗体反应相关。确定医护人员可能发生血清转化的可能性与某些医院部门有不同的关联，这可能会为将来的感染控制和职业卫生实践提供信息。3％），在重症监护室（14.8％）和急诊医学（13.3％）的参与者中观察到的比率较低。结论在一项针对卫生保健工作者的大型横断面血清流行病学研究中，我们证明了无症状的血清转化发生，但是先前有症状的疾病与定量更高的抗体反应相关。确定医护人员可能发生血清转化的可能性与某些医院部门有不同的关联，这可能会为将来的感染控制和职业卫生实践提供信息。3％），在重症监护室（14.8％）和急诊医学（13.3％）的参与者中观察到的比率较低。结论在一项针对卫生保健工作者的大型横断面血清流行病学研究中，我们证明了无症状的血清转化发生，但是先前有症状的疾病与定量更高的抗体反应相关。鉴定医护人员血清转化的潜力可以与某些医院部门有不同的关联，这可能会为将来的感染控制和职业卫生实践提供信息。