Asymptomatic Subclinical Cases of Coronavirus Disease 2019 without Viral Transmission in Three Independent Families

Infect Drug Resist. 2020 Sep 24;13:3267-3271. doi: 10.2147/IDR.S261304. eCollection 2020.


Purpose: There is increasing evidence indicating that considerable fractions of cases of SARS-CoV-2 infection are asymptomatic. We traced three asymptomatic clusters to investigate the infectivity of subclinical cases of coronavirus disease 2019 (COVID-19).

Patients and methods: Three medical staff who were asymptomatic were diagnosed with coronavirus disease 2019 by serological tests. Their close contacts were systematically evaluated based on COVID-19-related symptoms, nucleic acid tests, serological tests, and chest computed tomography (CT) as needed to determine if they were infected by SARS-CoV-2.

Results: None of the staff's close contacts, including 10 family members, were infected by the indexes, even though no protective measures were taken.

Conclusion: The infectivity of asymptomatic subclinical infection patients of coronavirus disease 2019 seems to be low.

Keywords: COVID-19; SARS-CoV-2; asymptomatic; close contact; infectivity.

Grant support

This work was supported by Emergency Research Project of Tongji hospital of Huazhong University of Science and Technology (Grant Number: 2020kfyXGYJ045, to Dr. JZ).