背景:由严重急性呼吸道综合征冠状病毒2(SARS-CoV-2)引起的新型冠状病毒病2019(COVID-19)是大流行的。然而,有关流行病学特征的数据,病毒脱落,无症状SARS-CoV-2携带者和COVID-19患者之间的抗体动态仍存在争议。
方法:我们在宁波和舟山招募了193名SARS-CoV-2感染者,浙江,中国,2020年1月21日至3月6日。对所有受试者进行随访,以使用胶体金标记和酶联免疫吸附试验监测血清抗体免疫球蛋白M(IgM)和IgG对SARS-CoV-2的动态。
结果:其中,31人是无症状的SARS-CoV-2携带者,148例有症状的COVID-19患者,和14例症状前COVID-19患者。与有症状的COVID-19患者相比,无症状携带者较年轻,白细胞和淋巴细胞水平较高,C反应蛋白水平较低,和较短的病毒脱落持续时间。无症状携带者的IgM从阳性到阴性的转化比COVID-19患者短(7.5vs.25.5天,P=0.030)。在COVID-19患者中,针对SARS-CoV-2的IgG持续血清阳性的比例高于无症状携带者(66.1%vs.33.3%,P=0.037)。有症状患者的病毒载量高于症状前患者(P=0.003)和无症状携带者(P=0.004)。症状前COVID-19患者的病毒脱落持续时间长于无症状携带者(48.0vs.24.0天,P=0.002)。无症状携带者比COVID-19患者更多地从家族内传播获得感染(89.0%vs.61.0%,P=0.028)。在4个SARS-CoV-2感染家族群中,无症状携带者主要为儿童和青少年,而严重COVID-19主要见于60岁以上有合并症的家庭成员.
结论:无症状携带者对清除SARS-CoV-2的抗病毒免疫力可能高于有症状的COVID-19患者,这种抗病毒免疫力应有助于先天和适应性细胞免疫,而不是体液免疫。COVID-19的严重程度与年龄和家族性聚集病例的合并症有关。
BACKGROUND: Novel coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is pandemic. However, data concerning the epidemiological features, viral shedding, and antibody dynamics between asymptomatic SARS-CoV-2 carriers and COVID-19 patients remain controversial.
METHODS: We enrolled 193 SARS-CoV-2 infected subjects in Ningbo and Zhoushan, Zhejiang,
China, from January 21 to March 6, 2020. All subjects were followed up to monitor the dynamics of serum antibody immunoglobulin M (IgM) and IgG against SARS-CoV-2 using colloidal gold-labeled and enzyme-linked immunosorbent assays.
RESULTS: Of those, 31 were asymptomatic SARS-CoV-2 carriers, 148 symptomatic COVID-19 patients, and 14 presymptomatic COVID-19 patients. Compared to symptomatic COVID-19 patients, asymptomatic carriers were younger and had higher levels of white blood cell and lymphocyte, lower level of C-reactive protein, and shorter viral shedding duration. Conversion of IgM from positive to negative was shorter in asymptomatic carriers than in COVID-19 patients (7.5 vs. 25.5 days, P = 0.030). The proportion of those persistently seropositive for IgG against SARS-CoV-2 was higher in COVID-19 patients than in asymptomatic carriers (66.1% vs. 33.3%, P = 0.037). Viral load was higher in symptomatic patients than presymptomatic patients (P = 0.003) and asymptomatic carriers (P = 0.004). Viral shedding duration was longer in presymptomatic COVID-19 patients than in asymptomatic carriers (48.0 vs. 24.0 days, P = 0.002). Asymptomatic carriers acquired infection more from intra-familial transmission than did COVID-19 patients (89.0% vs. 61.0%, P = 0.028). In 4 familial clusters of SARS-CoV-2 infection, asymptomatic carriers were mainly children and young adults while severe COVID-19 was mainly found in family members older than 60 years with comorbidities.
CONCLUSIONS: Asymptomatic carriers might have a higher antiviral immunity to clear SARS-CoV-2 than symptomatic COVID-19 patients and this antiviral immunity should be contributable to innate and adaptive cellular immunity rather than humoral immunity. The severity of COVID-19 is associated with older age and comorbidities in familial clustering cases.