Epidemiology

Physics

Internal medicine

Sociology

Disease

Infection rate

Coronavirus disease 2019 (COVID-19)

Infectious disease (medical specialty)

Incidence (geometry)

Pandemic

Optics

Outbreak

Demography

Surgery

Management

Virology

Emergency medicine

Economics

Case fatality rate

Coronavirus

Asymptomatic

2019-20 coronavirus outbreak

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)

Confidence interval

Medicine

Estimation

Journal of Clinical Medicine

From 29 to 31 January 2020, a total of 565 Japanese citizens were evacuated from Wuhan, China on three chartered flights. All passengers were screened upon arrival in Japan for symptoms consistent with novel coronavirus (2019-nCoV) infection and tested for presence of the virus. Assuming that the mean detection window of the virus can be informed by the mean serial interval (estimated at 7.5 days), the ascertainment rate of infection was estimated at 9.2% (95% confidence interval: 5.0, 20.0). This indicates that the incidence of infection in Wuhan can be estimated at 20,767 infected individuals, including those with asymptomatic and mildly symptomatic infections. The infection fatality risk (IFR)—the actual risk of death among all infected individuals—is therefore 0.3% to 0.6%, which may be comparable to Asian influenza pandemic of 1957–1958.

The Rate of Underascertainment of Novel Coronavirus (2019-nCoV) Infection: Estimation Using Japanese Passengers Data on Evacuation Flights