Background: Since the onset of the SARS-CoV-2 pandemic in late 2019, many studies suggest that actual infection rates may far exceed reported cases. Therefore, this study provides a comprehensive overview of anti-SARS-CoV-2 antibody measurements and their significance in epidemiological surveillance, especially regarding the true extent of SARS-CoV-2 infections, allowing more detailed insights into the dynamics of the pandemic.

Methods: Antibodies were measured using the Elecsys® Anti-SARS-CoV-2 assay for the nucleocapsid (N) protein and the SARS-CoV-2 IgG (sCOVG) assay for the spike (S) protein. A total of 25197 specimens from University Hospital Heidelberg were analyzed between May 2020 and December 2023, with 16957 samples measured for both antibodies, 2756 for anti-N only, and 5484 for anti-S only.For the epidemiological tracing of the SARS-CoV-2 incidence we analyzed changes in the anti-N positivity rate and anti-S positivity rate within our tertiary hospital setting across consecutive quarters.

Results: Anti-N measurements allowed for a retrospective analysis of SARS-CoV-2 epidemiological developments, revealing significant changes (p <0.05) in the anti-N positivity rate following incidence peaks (increase) and low incidence periods (decrease) with only three non-significant transitions.On the other hand, the anti-S positivity rate showed only four significant transitions between consecutive quarters.

Conclusion: The anti-N positivity rate is an effective and straightforward retrospective serological tool for tracking epidemiological trends, while the anti-S rate is influenced by vaccination and epidemiology as well, making it inept for the tracing of epidemiological changes. Although the recent development in SARS-CoV-2 epidemiology with increasing intervals between infection waves already provide an enhanced statistical robustness, we recommend the determination of the anti-N positivity rate in larger study populations.

Keywords: Antibody testing; COVID-19; ELISA; Epidemiological surveillance; Public health; SARS-CoV-2; Serological test.

© 2024 The Authors.

背景： 自2019年底SARS-CoV-2大流行开始以来，许多研究表明实际感染率可能远远超过报告的病例数。因此，本研究提供了针对抗SARS-CoV-2抗体测量及其在流行病学监测中的意义的全面概述，特别是在揭示SARS-CoV-2感染的真实范围方面，允许对大流行的动态有更详细的了解。

方法： 使用Elecsys® Anti-SARS-CoV-2试剂盒测量核衣壳（N）蛋白抗体，并使用SARS-CoV-2 IgG (sCOVG) 试剂盒测量刺突(S)蛋白抗体。总共分析了海德堡大学医院在2020年5月至2023年12月期间的25,197份样本，其中16,957份样本同时进行了两种抗体检测，2,756份样本仅进行抗N抗体检测，5,484份样本仅进行抗S抗体检测。为了追踪SARS-CoV-2发病率的变化，在我们三级医院的背景下分析了连续季度内的抗N阳性率和抗S阳性率的变化。

结果： 抗N测量允许回顾性地分析SARS-CoV-2流行病学发展情况，揭示了在发病率峰值期间（增加）以及低发病率时期（减少）的抗N阳性率具有显著变化 (p

结论： 抗N阳性率是一个有效且直观的回顾性血清学工具，用于追踪流行病学趋势；而抗S比率受到疫苗接种和流行病的影响，因此不适合追踪流行病的变化。尽管最近SARS-CoV-2流行病学的发展中感染波间隔时间增加已经提供了更强大的统计稳健性，但我们建议在更大规模的研究人群中确定抗N阳性率。

关键词： 抗体检测；COVID-19；ELISA；流行病学监测；公共卫生；SARS-CoV-2；血清学测试。