Epidemiologic characteristics of early cases with 2019 novel coronavirus (2019-nCoV) disease in Korea

Abstract

In about 20 days since the diagnosis of the first case of the 2019 novel coronavirus (2019-nCoV) in Korea on January 20, 2020, 28 cases have been confirmed. Fifteen patients (53.6%) of them were male and median age of was 42 years (range, 20-73). Of the confirmed cases, 16, 9, and 3 were index (57.2%), first-generation (32.1%), and second-generation (10.7%) cases, respectively. All first-generation and second-generation patients were family members or intimate acquaintances of the index cases with close contacts. Fifteen among 16 index patients had entered Korea from January 19 to 24, 2020 while 1 patient had entered Korea on January 31, 2020. The average incubation period was 3.9 days (median, 3.0), and the reproduction number was estimated as 0.48. Three of the confirmed patients were asymptomatic when they were diagnosed. Epidemiological indicators will be revised with the availability of additional data in the future. Sharing epidemiological information among researchers worldwide is essential for efficient preparation and response in tackling this new infectious disease.

Keywords: 2019-nCoV; Epidemiology; Isolation; Korea; Outbreak; Quarantine.

Figure 1.

Early 28 cases of 2019 novel coronavirus disease in Korea according to the chain of transmission.

Figure 2.

Epidemic curves of 2019 novel coronavirus disease outbreak for early 28 cases, Korea. (A) Curve according to symptom-onset date, (B) curve according to disease-confirmed date. The symptom-onset of #2 case was on January 10, 2020 in China and he entered Korea on January 22, 2020.

Figure 3.

Epidemic curves of 2019 novel coronavirus disease outbreak for early 28 cases by area, Korea. (A) Curve according to symptom-onset date, (B) curve according to confirmed date. The symptom-onset of #2 case was on January 10, 2020 in China and entered Korea on January 22, 2020.

Figure 4.

Early 28 cases of 2019 novel coronavirus disease by geographical area in Korea. The two cases that were evacuated from Wuhan were not included in this map.

Figure 5.

Summary of epidemiologic characteristics of early 28 patients diagnosed with 2019 novel coronavirus disease in Korea. M, male; F, female; Info, information.