Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2020 Oct:99:266-268.
doi: 10.1016/j.ijid.2020.08.001. Epub 2020 Aug 6.

Clinical Characteristics of Asymptomatic Patients with COVID-19: A Nationwide Cohort Study in South Korea

Chan-Young Jung  1 , Haeyong Park  2 , Dong Wook Kim  3 , Yoon Jung Choi  4 , Seong Woo Kim  5 , Tae Ik Chang  6
Affiliations

Clinical Characteristics of Asymptomatic Patients with COVID-19: A Nationwide Cohort Study in South Korea

Chan-Young Jung et al. Int J Infect Dis. 2020 Oct.

Abstract

Objectives: To delineate clinical characteristics of asymptomatic and symptomatic patients confirmed with COVID-19 in South Korea.

Methods: Data were obtained from the Korean National Health Insurance Service database linked to the Korea Centers for Disease Control and Prevention data.

Results: Among 10,237 patients (mean [SD] age, 45.0 [19.8] years; 60.1% female) who met the eligibility criteria for the study, 6,350 (62.0%) patients were asymptomatic, and 3,887(38.0%) patients were symptomatic. The mean and median age were similar between asymptomatic and symptomatic patients. Notably, we observed a U-shaped association between age group and the proportion of asymptomatic patients, with the nadir at 57.3% in the 40-49 age group. This U-shaped distribution was largely similar between men and women. The overall prevalence of asymptomatic individuals was higher, regardless of sex, residential area, income levels, and comorbid conditions.

Conclusions: In this national cohort of over 10,000 patients with COVID-19, more than 60% of all cases in South Korea reported no symptoms at the time of diagnosis. Expanding criteria for contact tracing and testing to capture potential transmission before symptom onset should be urgently considered to inform control strategies for COVID-19.

Keywords: Asymptomatic; COVID-19; SARS-COV-2.

PubMed Disclaimer

Figures

Figure 1
Figure 1
Asymptomatic Proportions across Age Groups among Patients with COVID-19 in South Korea. (A) Total population, (B) Stratified by sex.
See this image and copyright information in PMC

References

    1. Korea Ministry of Health and Welfare, Center for Disease Control and Prevention . 2020. The updates on COVID-19 in Korea: for press release. Available from: https://www.cdc.go.kr/board/board.es?mid=a30402000000&bid=0030. [Accessed July 2 2020]
    1. Song J.Y., Yun J.G., Noh J.Y., Cheong H.J., Kim W.J. Covid-19 in South Korea - Challenges of Subclinical Manifestations. N Engl J Med. 2020;382:1858–1859. - PMC - PubMed
    1. Bai Y., Yao L., Wei T., Tian F., Jin D.Y., Chen L. Presumed Asymptomatic Carrier Transmission of COVID-19. JAMA. 2020;323:1406–1407. - PMC - PubMed
    1. He X., Lau E.H.Y., Wu P., Deng X., Wang J., Hao X. Temporal dynamics in viral shedding and transmissibility of COVID-19. Nat Med. 2020;26:672–675. - PubMed
    1. Quan H., Sundararajan V., Halfon P., Fong A., Burnand B., Luthi J.C. Coding algorithms for defining comorbidities in ICD-9-CM and ICD-10 administrative data. Med Care. 2005;43:1130–1139. - PubMed