Novel coronavirus 2019-nCoV (COVID-19): early estimation of epidemiological parameters and epidemic size estimates

TLDR

The novel coronavirus (2019‑nCoV) emerged in Wuhan and rapidly spread across China and beyond. A transmission model estimated a basic reproductive number of 3.11 and a 5 % case ascertainment rate in Wuhan, implying that 58–76 % of transmissions must be blocked to halt growth. The model predicts 21 022 (11 090–33 490) infections in Wuhan from 1–22 January, far exceeding reported cases. The article appears in the theme issue “Modelling that shaped the early COVID‑19 pandemic response in the UK.”.

Abstract

Since it was first identified, the epidemic scale of the recently emerged novel coronavirus (2019-nCoV) in Wuhan, China, has increased rapidly, with cases arising across China and other countries and regions. Using a transmission model, we estimate a basic reproductive number of 3.11 (95% CI, 2.39–4.13), indicating that 58–76% of transmissions must be prevented to stop increasing. We also estimate a case ascertainment rate in Wuhan of 5.0% (95% CI, 3.6–7.4). The true size of the epidemic may be significantly greater than the published case counts suggest, with our model estimating 21 022 (prediction interval, 11 090–33 490) total infections in Wuhan between 1 and 22 January. We discuss our findings in the light of more recent information. This article is part of the theme issue ‘Modelling that shaped the early COVID-19 pandemic response in the UK’.