Graph showing the similarity of 2019-nCoV transmission to SARS-CoV and 1918 pandemic influenza (from ref. 1).

On December 31, 2019, the World Health Organization (WHO) was notified about a cluster of pneumonia of unknown origin in the city of Wuhan, China. Chinese authorities later identified a new coronavirus (2019-nCoV) as the causative agent of the outbreak. As of January 24, 2020, 911 cases have been confirmed in China and several other countries.

During the early stage of an outbreak, it is critically important to analyze the observed transmission pattern and the potential for sustained human-to-human transmission of 2019-nCoV. A better understanding of the transmissibility of the virus will help coordinate current screening and containment strategies, support decision making on whether the outbreak constitutes a public health emergency of international concern (PHEIC), and is key for anticipating the risk of pandemic spread of 2019-nCoV.

We estimated the basic reproduction number R0, which describes the average number of secondary cases generated by an infectious index case, at around 2.2 (90% high density interval 1.4-3.8), indicating the potential for sustained human-to-human transmission. The transmission characteristics and the potential for superspreading events appear to be similar to what was observed during the outbreak of severe acute respiratory syndrome-related coronavirus (SARS-CoV) in 2003, but are also consistent with what has been observed for influenza.

Given the current uncertainty around the case fatality rate, our findings highlight the importance of heightened screening, surveillance and control efforts, particularly at airports and other transportation hubs, in order to prevent further international spread of 2019-nCoV.

The R code files that were used for this analysis can be found on GitHub.

  1. Riou J, Althaus CL. (2020) Pattern of early human-to-human transmission of Wuhan 2019-nCoV. biorXiv, 01.23.917351.