Institute of Clinical Microbiology, University Hospital, 50005 Hradec Kralove, Czech Republic.
Faculty of Medicine in Hradec Kralove, Charles University, 50003 Hradec Kralove, Czech Republic.
Viruses. 2022 Mar 4;14(3):526. doi: 10.3390/v14030526.
The diagnosis of SARS-CoV-2 is almost exclusively performed by PCR or antigen detection. The detection of specific antibodies has not yet been considered in official diagnostic guidelines as major laboratory evidence for a case definition. The aim the present study is to analyze antibody responses in outpatient and inpatient cohorts of COVID-19 patients in the Czech Republic over a 12-month period, and assess the potential of antibodies as a diagnostic tool.
A total of 644 patients was enrolled in the prospective study. IgA, IgM and IgG antibody levels, as well as virus neutralization titers, were analyzed over a 12-month period.
Our study showed low antibody positivity levels at the admission. However, at 2 weeks after infection, 98.75% and 95.00% of hospitalized patients were IgA and IgG positive, respectively. Even in the outpatient cohort characterized by milder disease courses, the IgG antibody response was still sustained at 9 and 12 months. The data show a high correlation between the IgG levels and virus neutralization titers (VNTs). Samples from later time-points showed positive antibody responses after vaccination in both cohorts characterized by high IgG levels and VNT over 1:640. The samples from unvaccinated persons indicated a relatively high level of reinfection at 6.87%.
Our results show that the detection of antibodies against the SARS-CoV-2 shows an increasing sensitivity from week 2 after infection and remains highly positive over the 12-month period. The levels of IgG antibodies correlate significantly with the VNTs. This suggests that the serological data may be a valuable tool in the diagnosis of SARS-CoV-2 infection.
SARS-CoV-2 的诊断几乎完全通过 PCR 或抗原检测进行。特异性抗体的检测尚未被纳入官方诊断指南作为病例定义的主要实验室证据。本研究旨在分析捷克共和国 COVID-19 门诊和住院患者队列中 12 个月内的抗体反应，并评估抗体作为诊断工具的潜力。
共有 644 名患者参与了这项前瞻性研究。分析了 IgA、IgM 和 IgG 抗体水平以及病毒中和滴度在 12 个月内的变化。
我们的研究显示入院时的抗体阳性率较低。然而，在感染后 2 周时，住院患者的 IgA 和 IgG 阳性率分别为 98.75%和 95.00%。即使在疾病较轻的门诊患者队列中，IgG 抗体反应在 9 个月和 12 个月时仍持续存在。数据显示 IgG 水平与病毒中和滴度（VNT）之间存在高度相关性。在两个队列中，来自后期时间点的样本在 IgG 水平和 VNT 均超过 1:640 时，接种疫苗后显示出阳性抗体反应。未接种疫苗的样本在 6.87%时显示出相对较高的再次感染水平。
我们的结果表明，针对 SARS-CoV-2 的抗体检测从感染后第 2 周开始显示出越来越高的敏感性，并在 12 个月内保持高度阳性。IgG 抗体水平与 VNTs 显著相关。这表明血清学数据可能是 SARS-CoV-2 感染诊断的有用工具。
