Beijing Center for Disease Prevention and Control, Beijing, China.
Beijing Research Center for Preventive Medicine, Beijing, China.
Clin Infect Dis. 2020 Dec 17;71(10):2688-2694. doi: 10.1093/cid/ciaa721.
Coronavirus disease 2019 (COVID-19) is a pandemic with no specific antiviral treatments or vaccines. There is an urgent need for exploring the neutralizing antibodies from patients with different clinical characteristics.
A total of 117 blood samples were collected from 70 COVID-19 inpatients and convalescent patients. Antibodies were determined with a modified cytopathogenic neutralization assay (NA) based on live severe acute respiratory syndrome coronavirus 2 and enzyme-linked immunosorbent assay (ELISA). The dynamics of neutralizing antibody levels at different time points with different clinical characteristics were analyzed.
The seropositivity rate reached up to 100.0% within 20 days since onset, and remained 100.0% till days 41-53. The total geometric mean titer was 1:163.7 (95% confidence interval [CI], 128.5-208.6) by NA and 1:12 441.7 (95% CI, 9754.5-15 869.2) by ELISA. The antibody level by NA and ELISA peaked on days 31-40 since onset, and then decreased slightly. In multivariate generalized estimating equation analysis, patients aged 31-45, 46-60, and 61-84 years had a higher neutralizing antibody level than those aged 16-30 years (β = 1.0470, P = .0125; β = 1.0613, P = .0307; β = 1.3713, P = .0020). Patients with a worse clinical classification had a higher neutralizing antibody titer (β = 0.4639, P = .0227).
The neutralizing antibodies were detected even at the early stage of disease, and a significant response was shown in convalescent patients.
2019 年冠状病毒病（COVID-19）是一种大流行疾病，目前尚无特定的抗病毒治疗或疫苗。因此，迫切需要探索具有不同临床特征的患者的中和抗体。
共采集了 70 例 COVID-19 住院患者和康复患者的 117 份血样。采用基于活严重急性呼吸综合征冠状病毒 2 的改良细胞病变中和测定（NA）和酶联免疫吸附测定（ELISA）检测抗体。分析不同临床特征的患者在不同时间点的中和抗体水平动态变化。
发病后 20 天内血清阳性率达到 100.0%，发病后 41-53 天仍保持 100.0%。NA 检测的总几何平均滴度为 1:163.7（95%置信区间[CI]，128.5-208.6），ELISA 检测的总几何平均滴度为 1:12441.7（95%CI，9754.5-15869.2）。NA 和 ELISA 检测的抗体水平在发病后 31-40 天达到峰值，然后略有下降。在多变量广义估计方程分析中，年龄在 31-45、46-60 和 61-84 岁的患者比 16-30 岁的患者具有更高的中和抗体水平（β=1.0470，P=0.0125；β=1.0613，P=0.0307；β=1.3713，P=0.0020）。临床分级较差的患者具有更高的中和抗体滴度（β=0.4639，P=0.0227）。
即使在疾病早期也可检测到中和抗体，并且在康复患者中显示出明显的反应。
