Background

This study aimed to compare four anti-SARS-CoV-2 immunoassays in populations presenting different clinical severity levels.

Methods

Three populations were included: “severe-to-critical” ICU-hospitalized patients (n = 18), “mild-to-moderate” hospitalized patients (n = 16) and non-hospitalized symptomatic patients (n = 24). Four commercial immunoassays were analyzed and validated: anti-IgG ARCHITECT® (Abbott), anti-Total antibodies (Ab) VITROS® (Ortho Clinical Diagnostics), anti-IgG NovaLisa® (NovaTec Immundiagnostica) and Healgen® IgM and IgG (Zhejiang Orient Gene Biotech). Sensitivities were evaluated according to days post-symptoms onset (pso). Specificities were evaluated on SARS-CoV-2-negative control sera collected before January 2020.

Results

A majority of severe-to-critically ill patients showed detectable Ab already at day 14 and sensitivities reached 100 % after 22 days pso. For patients with “mild-to-moderate” illness, sensitivities increased by at least 5-fold from day 0 to day 14 pso. Non-hospitalized symptomatic individuals already seroconverted at day 14 days pso with 100 % sensitivities for Total Ab VITROS®. Specificities were evaluated at 97 % for ARCHITECT® and NovaLisa®, 98 % for VITROS® and at 94 % for Healgen® combined IgM and IgG. Five “severe-to-critically” ill patients presented high positive Ab levels for at least 16 weeks pso.

Conclusion

The Ab levels and the evaluated sensitivities, representing the true positive rate, increased overtime and were related to the COVID-19 severity. Automated Total Ab immunoassay showed better sensitivities and specificity for immunological surveillance and vaccine evaluation.

中文翻译：

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住院患者和非卧床患者中四种商业SARS-CoV-2血清学免疫测定的分析和临床评估

背景

这项研究旨在比较表现出不同临床严重性水平的人群中的四种抗SARS-CoV-2免疫测定。

方法

包括三个人群：“重度至重度” ICU住院患者（n = 18），“轻度至中度”住院患者（n = 16）和非住院症状患者（n = 24）。分析并验证了四种商业免疫测定法：抗IgG抗体（Abbott），抗全抗体（Ab）VITROS®（Ortho Clinical Diagnostics），抗IgGNovaLisa®（NovaTec Immundiagnostica）和Healgen®IgM和IgG（浙江东方）基因生物技术）。根据症状发作后的天数（pso）评估敏感性。对2020年1月之前收集的SARS-CoV-2阴性对照血清进行了特异性评估。

结果

大多数重症至重症患者在第14天就已经显示出可检测到的Ab，pso 22天后敏感性达到100％。对于患有“轻度至中度”疾病的患者，敏感性从第0天到第14天增加了至少5倍。非住院的有症状个体在pso第14天已经血清转化，对Total AbVITROS®的敏感性为100％。评估的特异性为ARCHITECT®和NovaLisa®，特异性为97％，VITROS®为98％，Healgen®结合的IgM和IgG为94％。5名“重症至重症”患者在至少16周内表现出高的阳性抗体水平。

结论

代表真实阳性率的Ab水平和评估的敏感性随着时间的推移而增加，并且与COVID-19严重程度有关。全自动Total Ab免疫测定对免疫学监测和疫苗评估显示出更好的敏感性和特异性。