Novel coronavirus 2019-nCoV: early estimation of epidemiological parameters and epidemic predictions

Jonathan M Read; Jessica RE Bridgen; Derek AT Cummings; Antonia Ho; Chris P Jewell

We estimated the transmission rate within Wuhan, , to be 1.94 d -1 (95%CI, 1.25-6.71), while we found the infectious period to be 1.61 days (95%CI, 0.35-3.23). We calculated the basic reproductive number, 0 , of the infection to be 3.11 (95%CI, 2.39-4.13), comparable to the range for SARS estimated from outbreaks during the 2003 epidemic (Lipsitch et al., 2003; World Health Organization, 2003) . We highlight that this number is highly uncertain and that a large range of parameters are consistent with the data given the assumptions of our model. This estimate reflects both the dynamics of transmission and, potentially, the dynamics of case reporting, with increases as reporting over time potentially increasing our estimate. The estimate we give here represents an update from the report of 23 January in which we estimated a higher 0 , and highlights the sensitivity of our findings to additional data at this early period. The current estimate of 0 is significantly greater than 1, the epidemic threshold, providing evidence that sustained human-to-human transmission is occurring in China. Further, it suggests that a concerted effort will be required to control the outbreak, requiring between 38% and 80% of transmission to be averted to control the epidemic.