COVID-19 is a pandemic caused by SARS-CoV-2. In Chile, half a million people have been infected and more than 16,000 have died from COVID-19. As part of the clinical trial NCT04384588, we quantified IgG against S1-RBD of SARS-CoV-2 (anti-RBD) in recovered people in Santiago and evaluated their suitability as COVID-19 convalescent plasma donors. ELISA and a luminescent SARS-CoV-2 pseudotype were used for IgG and neutralizing antibody quantification. 72.9% of the convalescent population (468 of 639) showed seroconversion (5-55 μg/mL anti-RBD IgG) and were suitable candidates for plasma donation. Analysis by gender, age, and days after symptom offset did not show significant differences. Neutralizing activity correlated with an increased concentration of anti-RBD IgG () and showed a high variability between donors. We confirmed that the majority of the Chilean patients have developed anti-SARS-CoV-2 antibodies. The quantification of anti-RBD IgG in convalescent plasma donors is necessary to increase the detection of neutralizing antibodies.

中文翻译：

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智利人群中针对SARS-CoV-2 S1-RBD的IgG抗体血清转换和中和活性。

COVID-19是由SARS-CoV-2引起的大流行。在智利，有50万人被感染，超过16,000人死于COVID-19。作为临床试验NCT04384588的一部分，我们在圣地亚哥恢复的人群中定量了针对SARS-CoV-2的S1-RBD的IgG（抗RBD），并评估了其作为COVID-19康复血浆供体的适用性。ELISA和发光的SARS-CoV-2假型用于IgG和中和抗体定量。恢复期人口（639 468）的72.9％，表现出血清转化（5-55  μ克/ mL抗RBD IgG）和分别用于血浆捐献的合适候选者。按性别，年龄和症状消除后天数进行的分析未显示显着差异。中和活性与抗-RBD IgG（），并显示出供体之间的高度变异性。我们确认大多数智利患者已开发出抗SARS-CoV-2抗体。恢复性血浆供体中抗RBD IgG的定量对增加中和抗体的检测是必要的。