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Clinical Characteristics of 24 Asymptomatic Infections with COVID-19 Screened Among Close Contacts in Nanjing, China

27 Pages Posted: 28 Feb 2020

See all articles by Zhiliang Hu

Zhiliang Hu

Nanjing University of Chinese Medicine (NJUCM) - Department of Anesthesiology, Tuberculosis and Infectious Disease

Ci Song

Nanjing Medical University - Department of Epidemiology and Biostatistics

Chuanjun Xu

Nanjing University of Chinese Medicine (NJUCM) - Department of Radiology

Guangfu Jin

Nanjing Medical University - Department of Epidemiology and Biostatistics

Yaling Chen

Nanjing University of Chinese Medicine (NJUCM) - Nanjing Infectious Disease Center

Xin Xu

Nanjing Medical University - Department of Epidemiology and Biostatistics

Hongxia Ma

Nanjing Medical University - Department of Epidemiology and Biostatistics

Wei Chen

Nanjing University of Chinese Medicine (NJUCM) - Department of Clinical Research Center

Yuan Lin

Nanjing Medical University - Department of Maternal, Child and Adolescent Health

Yishan Zheng

Nanjing University of Chinese Medicine (NJUCM) - Department of Critical Medicine

Jianming Wang

Nanjing Medical University - Department of Epidemiology and Biostatistics

Zhibin Hu

Nanjing Medical University - Department of Epidemiology and Biostatistics

Yongxiang Yi

Nanjing University of Chinese Medicine (NJUCM) - Nanjing Infectious Disease Center

Hongbing Shen

Nanjing Medical University - Department of Epidemiology and Biostatistics

More...

Abstract

Background: 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.

Methods: 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.

Findings: None of the 24 asymptomatic cases presented any obvious symptoms before nucleic acid screening. Five cases (20.8%) developed symptoms (fever, cough, fatigue and 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.

Interpretation: 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.

Funding Statement: This study was funded in part by the project of Jiangsu province medical youth talent (QNRC2016059), Nanjing medical science and technique development foundation (ZKX17040 and YKK18153), the National Natural Science Foundation of China (81903382), Cheung Kong Scholars Program of China

Declaration of Interests: The authors declare no competing interests.

Ethics Approval Statement: This study was reviewed and approved by the Medical Ethical Committee of Second Hospital of Nanjing (approval number 2020-LS-ky003).

Keywords: COVID-19; Asymptomatic Infection; Close Contact; China

Suggested Citation

Hu, Zhiliang and Song, Ci and Xu, Chuanjun and Jin, Guangfu and Chen, Yaling and Xu, Xin and Ma, Hongxia and Chen, Wei and Lin, Yuan and Zheng, Yishan and Wang, Jianming and Hu, Zhibin and Yi, Yongxiang and Shen, Hongbing, Clinical Characteristics of 24 Asymptomatic Infections with COVID-19 Screened Among Close Contacts in Nanjing, China (February 21, 2020). Available at SSRN: https://ssrn.com/abstract=3543598 or http://dx.doi.org/10.2139/ssrn.3543598

Zhiliang Hu

Nanjing University of Chinese Medicine (NJUCM) - Department of Anesthesiology, Tuberculosis and Infectious Disease

Nanjing
China

Ci Song

Nanjing Medical University - Department of Epidemiology and Biostatistics

Nanjing, 211166
China

Chuanjun Xu

Nanjing University of Chinese Medicine (NJUCM) - Department of Radiology

China

Guangfu Jin

Nanjing Medical University - Department of Epidemiology and Biostatistics

Nanjing
China

Yaling Chen

Nanjing University of Chinese Medicine (NJUCM) - Nanjing Infectious Disease Center

China

Xin Xu

Nanjing Medical University - Department of Epidemiology and Biostatistics

Nanjing, 211166
China

Hongxia Ma

Nanjing Medical University - Department of Epidemiology and Biostatistics

Nanjing
China

Wei Chen

Nanjing University of Chinese Medicine (NJUCM) - Department of Clinical Research Center

China

Yuan Lin

Nanjing Medical University - Department of Maternal, Child and Adolescent Health

China

Yishan Zheng

Nanjing University of Chinese Medicine (NJUCM) - Department of Critical Medicine

China

Jianming Wang

Nanjing Medical University - Department of Epidemiology and Biostatistics ( email )

Nanjing
China
+86 25 86868438 (Phone)

Zhibin Hu

Nanjing Medical University - Department of Epidemiology and Biostatistics ( email )

Nanjing
China

Yongxiang Yi (Contact Author)

Nanjing University of Chinese Medicine (NJUCM) - Nanjing Infectious Disease Center ( email )

China

Hongbing Shen

Nanjing Medical University - Department of Epidemiology and Biostatistics ( email )

Nanjing
China

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