Risk for Transportation of 2019 Novel Coronavirus (COVID-19) from Wuhan to Cities in China

Zhanwei Du; Ling Wang; Simon Cauchemez; Xiaoke Xu; Xianwen Wang; Benjamin J Cowling; Lauren Ancel Meyers

We assume that visitors to Wuhan have the same daily risk for infection as residents of Wuhan and construct a nonhomogeneous Poisson process model ( 18 -20 ) to estimate the exportation of COVID-19 by residents of and travelers to Wuhan. Let W j , t denote the number of Wuhan residents that travel to city j at time t , and M j , t denote the number of travelers from city j to Wuhan at time t. Then, the rate at which infected residents of Wuhan travel to city j at time t is given γ j , t = ξ( t ) × W j , t , and the rate at which travelers from city j get infected in Wuhan and return to their home city while still infected is Ψ j , t = ξ( t ) × M j , t . This model assumes that newly infected visitors to Wuhan will return to their home city while still infectious.