Xiao Tongyang, Wang Yanrong, Yuan Jing, Ye Haocheng, Wei Lanlan, Liao Xuejiao, Wang Haiyan, Qian Shen, Wang Zhaoqin, Liu Lei, Zhang Zheng
National Clinical Research Center for Infectious Disease, School of Medicine, Institute of Hepatology, Shenzhen Third People's Hospital, The Second Affiliated Hospital, Southern University of Science and Technology, Shenzhen, China.
Department of Pediatrics, National Clinical Research Center for Infectious Disease, Shenzhen Third People's Hospital, Shenzhen, China.
Front Med (Lausanne). 2021 Mar 15;8:595773. doi: 10.3389/fmed.2021.595773. eCollection 2021.
Asymptomatic carriers contribute to the spread of Coronavirus Disease 2019 (COVID-19), but their clinical characteristics, viral kinetics, and antibody responses remain unclear. A total of 56 COVID-19 patients without symptoms at admission and 19 age-matched symptomatic patients were enrolled. RNA of SARS-CoV-2 was tested using transcriptase quantitative PCR, and the total antibodies (Ab), IgG, IgA, and IgM against the SARS-CoV-2 were tested using Chemiluminescence Microparticle Immuno Assay. Among 56 patients without symptoms at admission, 33 cases displayed symptoms and 23 remained asymptomatic throughout the follow-up period. 43.8% of the asymptomatic carriers were children and none of the asymptomatic cases had recognizable changes in C-reactive protein or interleukin-6, except one 64-year-old patient. The initial threshold cycle value of nasopharyngeal SARS-CoV-2 in asymptomatic carriers was similar to that in pre-symptomatic and symptomatic patients, but the positive viral nucleic acid detection period of asymptomatic carriers (9.63 days) was shorter than pre-symptomatic patients (13.6 days). There were no obvious differences in the seropositive conversion rate of total Ab, IgG, and IgA among the three groups, though the rates of IgM varied largely. The average peak IgG and IgM COI of asymptomatic cases was 3.5 and 0.8, respectively, which is also lower than those in symptomatic patients with peaked IgG and IgM COI of 4.5 and 2.4 ( < 0.05). Young COVID-19 patients seem to be asymptomatic cases with early clearance of SARS-CoV-2 and low levels of IgM generation but high total Ab, IgG, and IgA. Our findings provide empirical information for viral clearance and antibody kinetics of asymptomatic COVID-19 patients.
无症状携带者促成了2019冠状病毒病（COVID-19）的传播，但其临床特征、病毒动力学和抗体反应仍不清楚。共纳入56例入院时无症状的COVID-19患者和19例年龄匹配的有症状患者。采用转录酶定量PCR检测严重急性呼吸综合征冠状病毒2（SARS-CoV-2）的RNA，采用化学发光微粒子免疫分析检测针对SARS-CoV-2的总抗体（Ab）、IgG、IgA和IgM。在56例入院时无症状的患者中，33例出现症状，23例在整个随访期间保持无症状。43.8%的无症状携带者为儿童，除1例64岁患者外，无症状病例的C反应蛋白或白细胞介素-6均无明显变化。无症状携带者鼻咽部SARS-CoV-2的初始阈值循环值与症状前和有症状患者相似，但无症状携带者的病毒核酸阳性检测期（9.63天）短于症状前患者（13.6天）。三组之间总Ab、IgG和IgA的血清阳转率无明显差异，尽管IgM的阳转率差异很大。无症状病例的平均IgG和IgM COI峰值分别为3.5和0.8，也低于有症状患者，其IgG和IgM COI峰值分别为4.5和2.
