Epidemiological and clinical features of the 2019 novel coronavirus outbreak in China

Abstract

Background: The ongoing outbreak of the 2019 novel coronavirus (2019-nCoV) in China has led to the declaration of Public Health Emergency of International Concern by the World Health Organization. Methods: All 2019-nCoV infected patients reported to Chinese Center for Disease Control and Prevention up to 26 January 2020 were included for analysis. Disease and death incidence were compared between demographic groups and baseline conditions. Case fatality rates (CFRs) and the basic reproductive number R0 was estimated with a transmission model. Results: As of 26 January 2020, a total of 8866 patients including 4021 (45.35%) laboratory confirmed patients were reported from 30 provinces. Nearly half of the patients were aged 50 years or older (47.7%). There was a clear gender difference in incidence with 0.31 (male) vs. 0.27 (female) per 100,000 people (P<0.001). The median incubation period was 4.75 (interquartile range: 3.0-7.2) days. About 25.5%, 69.9% and 4.5% patients were diagnosed with severe pneumonia, mild pneumonia, and non-pneumonia, respectively. The overall CFR was estimated be 3.06% (95% CI 2.02-4.59%), but male patients, ≥60 years old, baseline diagnosis of severe pneumonia and delay in diagnosis were associated with substantially elevated CFR. The R0 was estimated to be 3.77 (95% CI 3.51-4.05), ranging 2.23-4.82 in sensitivity analyses varying the incubation and infectious periods. Conclusions: Compared with SARS-CoV, 2019-nCoV had comparable transmissibility and lower CFR. Our findings based on individual-level surveillance data emphasize the importance of early detection of elderly patients, particularly males, before symptoms progress to severe pneumonia.