Imperial College London research

On 17 January, a research group from the Imperial College London in the United Kingdom published a report that there had been 1,723 cases (95% confidence interval, 427–4,471) with the onset of symptoms by 12 January. This was based on the pattern of the initial spread to Thailand and Japan. They also concluded that "self-sustaining human-to-human transmission should not be ruled out", which has since been confirmed. As further cases came to light, they later recalculated that there may be 4,000 symptomatic cases of 2019-nCoV in Wuhan City by 18 January (uncertainty range of 1,000 to 9,700). A Hong Kong University group has reached a similar conclusion as the earlier study, with additional detail on transport within China.