Estimating number of global importations of COVID-19 from Wuhan, risk of transmission outside mainland China and COVID-19 introduction index between countries outside mainland China

Haoyang Sun; Borame Lee Dickens; Mark Chen; Alex Richard Cook; Hannah Eleanor Clapham

Therefore in this paper we estimate 1) the number of imported cases globally from Wuhan (using flight data and the currently reported cases), then using our estimates of the number of imported cases and current estimates of R0 for SARS-CoV-2 we estimate, 2) the probability of an outbreak in countries outside mainland China, and finally given this outbreak risk and the flights between countries outside mainland China, we estimate 3) the risk index for importations occurring from and to countries outside mainland China. There is, of course, large uncertainty in these values and we propagate the uncertainty through the estimates.