Clinical characteristics of 24 asymptomatic infections with COVID-19 screened among close contacts in Nanjing, China
Clinical characteristics of 24 asymptomatic infections with COVID-19 screened among close contacts in Nanjing, China
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中国南京市密切接触者中筛查出的24例COVID-19无症状感染者的临床特征
DOI：
10.1007/s11427-020-1661-4
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发表时间：
2020-03-04
影响因子：
9.1
通讯作者：
Shen, Hongbing
中科院分区：
文献类型：
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作者：
Hu, Zhiliang;Song, Ci;Shen, Hongbing
此前的研究已经显示了2019新型冠状病毒病（COVID-19）患者的临床特征以及人传人的证据。关于无症状感染者的数据有限。本研究旨在呈现从密切接触者中筛查出的24例无症状感染者的临床特征，并显示无症状的COVID-19病毒携带者的传播潜力。 2020年1月28日至2月9日，对中国江苏省南京市所有COVID-19患者（或疑似患者）的密切接触者在诊所和社区进行了流行病学调查。通过检测咽拭子样本的核酸，实验室确认无症状携带者对 COVID-19 病毒呈阳性。他们的临床记录、实验室评估和胸部 CT 扫描都经过审查。结果，24名无症状感染者在核酸筛查中均未出现明显症状。 5例（20.8%）在住院期间出现症状（发热、咳嗽、乏力等）。 12例（50.0%）表现为典型的磨玻璃胸CT图像，5例（20.8%）表现为肺部条纹阴影。其余7例（29.2%）CT影像正常，住院期间无症状。这7例患者比其他病例更年轻（中位年龄：14.0岁；P=0.012）。 24 例病例均未出现严重的 COVID-19 肺炎或死亡。中位传染期（从核酸检测阳性第一天到连续阴性检测第一天的间隔）为9.5天（24例无症状感染者中最长为21天）。通过流行病学调查，我们观察到典型的同居家庭成员无症状传播，甚至导致严重的COVID-19肺炎。总体而言，从密切接触者中发现的无症状感染者在住院期间容易出现轻症。然而，传染期可能长达三周，并且被传染的患者可能会发展为重症。这些结果凸显了通过病毒核酸检测进行密切接触者追踪和纵向监测的重要性。还可能会建议出院患者进一步隔离和持续核酸检测。
Previous studies have showed clinical characteristics of patients with the 2019 novel coronavirus disease (COVID-19) and the evidence of person-to-person transmission. Limited data are available for asymptomatic infections. This study aims to present the clinical characteristics of 24 cases with asymptomatic infection screened from close contacts and to show the transmission potential of asymptomatic COVID-19 virus carriers. Epidemiological investigations were conducted among all close contacts of COVID-19 patients (or suspected patients) in Nanjing, Jiangsu Province, China, from Jan 28 to Feb 9, 2020, both in clinic and in community. Asymptomatic carriers were laboratory-confirmed positive for the COVID-19 virus by testing the nucleic acid of the pharyngeal swab samples. Their clinical records, laboratory assessments, and chest CT scans were reviewed. As a result, none of the 24 asymptomatic cases presented any obvious symptoms while nucleic acid screening. Five cases (20.8%) developed symptoms (fever, cough, fatigue, etc.) during hospitalization. Twelve (50.0%) cases showed typical CT images of ground-glass chest and 5 (20.8%) presented stripe shadowing in the lungs. The remaining 7 (29.2%) cases showed normal CT image and had no symptoms during hospitalization. These 7 cases were younger (median age: 14.0 years; P=0.012) than the rest. None of the 24 cases developed severe COVID-19 pneumonia or died. The median communicable period, defined as the interval from the first day of positive nucleic acid tests to the first day of continuous negative tests, was 9.5 days (up to 21 days among the 24 asymptomatic cases). Through epidemiological investigation, we observed a typical asymptomatic transmission to the cohabiting family members, which even caused severe COVID-19 pneumonia. Overall, the asymptomatic carriers identified from close contacts were prone to be mildly ill during hospitalization. However, the communicable period could be up to three weeks and the communicated patients could develop severe illness. These results highlighted the importance of close contact tracing and longitudinally surveillance via virus nucleic acid tests. Further isolation recommendation and continuous nucleic acid tests may also be recommended to the patients discharged.