Alliance for Pandemic Preparedness

February 12, 2020

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



  • A review of all 2019-nCoV patients reported to the Chinese Center for Disease Control and Prevention (Chinese CDC) up to 26 January, 2020 was undertaken to describe the affected populations and to estimate severity and transmissibility.
  • Of 8866 patients, 4021 (45%) were laboratory confirmed. 
    • Ages were similar between confirmed and suspect cases (49 years; SD, +16 yrs). Fourteen of the 4021 confirmed cases were in children <10 years old. Most confirmed cases were 30-65 years of age.
    • Wuhan patients were on average older and more likely to be male compared to elsewhere in China. 
    • Among confirmed cases, median time from symptom onset to diagnosis was 5 days. Mild pneumonia (70%) was most often seen at time of diagnosis, with about 26% diagnosed with severe pneumonia and 5% with no evidence of pneumonia. 
    • Incidence shifted from sporadic to exponential on 1 January. Starting 17 January, more confirmed patients were reported outside of Wuhan than in Wuhan.
  • Bias-adjusted Case Fatality Rate (CFR) estimates: 
    • Among confirmed cases, calculated CFRs were higher than observed CFRs (3.1% and 1.4%, respectively). 
    • Ranged from 0.7% for those with mild disease at time of diagnosis to 9.5% for patients with two of three risks (male, >60 years of age, or severe disease at diagnosis) 
    • Were higher in patients >60 years of age (5.3% vs. 1.4% <60 yrs), patients with longer time from onset to diagnosis (3.1%, >5 days vs. 1.3%, <5), and among males (4.5% vs. 1.3%)
  • R0 estimates were highest (R0, 3.2-4.8) for long incubation (6.4 days) and infectious (9.2 days) periods; and lowest (R0, 2.2-2.8) for short incubation (3.8 days) and infectious (5.2 days) periods, with added variability due to reporting rate(30%-100%).

Yang Y, et al (Feb 11, 2020) Epidemiological and clinical features of the 2019 novel coronavirus outbreak in China. Pre-print accessed Feb 12 from