ISGlobal, Hospital Clínic, Universitat de Barcelona, Barcelona, Catalonia, Spain.
Spanish Consortium for Research in Epidemiology and Public Health, Madrid, Spain.
J Infect Dis. 2021 Jan 4;223(1):62-71. doi: 10.1093/infdis/jiaa696.
At the COVID-19 spring 2020 pandemic peak in Spain, prevalence of SARS-CoV-2 infection in a cohort of 578 randomly selected health care workers (HCWs) from Hospital Clínic de Barcelona was 11.2%.
A follow-up survey 1 month later (April-May 2020) measured infection by rRT-PCR and IgM, IgA, and IgG to the receptor-binding domain of the spike protein by Luminex. Antibody kinetics, including IgG subclasses, was assessed until month 3.
At month 1, the prevalence of infection measured by rRT-PCR and serology was 14.9% (84/565) and seroprevalence 14.5% (82/565). We found 25 (5%) new infections in 501 participants without previous evidence of infection. IgM, IgG, and IgA levels declined in 3 months (antibody decay rates 0.15 [95% CI, .11-.19], 0.66 [95% CI, .54-.82], and 0.12 [95% CI, .09-.16], respectively), and 68.33% of HCWs had seroreverted for IgM, 3.08% for IgG, and 24.29% for IgA. The most frequent subclass responses were IgG1 (highest levels) and IgG2, followed by IgG3, and only IgA1 but no IgA2 was detected.
Continuous and improved surveillance of SARS-CoV-2 infections in HCWs remains critical, particularly in high-risk groups. The observed fast decay of IgA and IgM levels has implications for seroprevalence studies using these isotypes.
在西班牙 2020 年春季 COVID-19 大流行高峰期，巴塞罗那 Clinic 医院的 578 名随机选择的卫生保健工作者（HCWs）队列中 SARS-CoV-2 感染的流行率为 11.2%。
一个月后（2020 年 4 月至 5 月）进行了一项随访调查，通过实时 RT-PCR 和 Luminex 测量了受体结合域的 IgM、IgA 和 IgG 来测量感染情况。评估了抗体动力学，包括 IgG 亚类，直到第 3 个月。
在第 1 个月，通过 rRT-PCR 和血清学测量的感染率为 14.9%（84/565）和血清流行率为 14.5%（82/565）。我们在 501 名没有先前感染证据的参与者中发现了 25 例（5%）新感染。IgM、IgG 和 IgA 水平在 3 个月内下降（抗体衰减率分别为 0.15[95%CI，0.11-0.19]、0.66[95%CI，0.54-0.82]和 0.12[95%CI，0.09-0.16]），68.33%的 HCWs 对 IgM 发生了血清学逆转，3.08%对 IgG 发生了血清学逆转，24.29%对 IgA 发生了血清学逆转。最常见的亚类反应是 IgG1（最高水平）和 IgG2，其次是 IgG3，仅检测到 IgA1 而未检测到 IgA2。
对 HCWs 的 SARS-CoV-2 感染进行持续和改进的监测仍然至关重要，特别是在高风险人群中。观察到 IgA 和 IgM 水平的快速衰减对使用这些同种型的血清流行率研究具有影响。
