How many people might one person with coronavirus infect?

Because the disease, which experts have named Covid-19, is infecting humans for the first time, there is no conferred immunity from previous exposure or vaccination. Everyone can potentially catch it, and, according to the MRC Centre for Global Infectious Disease Analysis at Imperial College London, the virus has an R0 of 1.5 to 3.5.

“Right now, coronavirus is much more of a concern than SARS ever was,” said Steven Riley, a professor of infectious-disease dynamics at Imperial College, referring to the global outbreak in 2003, when 8,096 people got sick and 774 died. “The main reason is our estimate of the number of people who are currently infectious is higher than the maximum who were ever infectious at one time with SARS.”