Real-time tentative assessment of the epidemiological characteristics of novel coronavirus infections in Wuhan, China, as at 22 January 2020 (2020/01/25)

Four strains of coronaviruses are known to spread easily in humans, causing generally-mild acute respiratory illnesses known as the common cold [1]. A much larger number of coronaviruses have been detected in animals, particularly in bats, but have not been found in humans [2]. Prior to December 2019 when clusters of pneumonia cases with unknown aetiology were detected in Wuhan, China, only two additional strains of coronaviruses had caused outbreaks of severe acute respiratory disease around the world [3]. In the 2003 outbreaks of severe acute respiratory syndrome coronavirus (SARS-CoV) infections in mainland China, Hong Kong and a number of other locations, there were more than 8,000 documented cases and 774 deaths [4]. Since 2012, outbreaks of Middle East respiratory syndrome coronavirus (MERS-CoV) infection have occurred in the Middle East [5], and in 2015, there was a large outbreak in South Korea [6,7]. Super-spreading events have contributed to large outbreaks of SARS-CoV and MERS-CoV [810].

On 9 January 2020, a novel coronavirus, 2019-nCoV, was officially identified as the cause of an outbreak of viral pneumonia in Wuhan, China [11]. Wuhan is a large city of more than 11 million people located in central China around 1,200 km south of Beijing. As of 22 January, there have been 440 confirmed 2019-nCoV infections reported in 13 provinces and municipalities in mainland China and five other countries and regions overseas, with an increasing number of cases reported in recent days (Figure 1). Here, we describe the preliminary epidemiological characteristics of 2019-nCoV infections based on publicly-available information (including some media reports) before an official ‘line list’ of confirmed cases becomes available.

Author: Peng Wu, Xinxin Hao, Eric H Y Lau, et al.