Temporal relationship between outbound traffic from Wuhan and the 2019 coronavirus disease (COVID-19) incidence in China

Zaixing Shi; Ya Fang

Another possible reason for the prolonged impact of migration in provinces adjacent to Hubei is that cross-province migrations are hard to shut off given the geographical proximity. Sporadic travelers from Wuhan may continue to cross provincial borders and spread the virus for a while after the travel ban. This is evident by the fact that the lag was much shorter in provinces further away from Wuhan (e.g., Tibet, Qinghai, Xinjiang, Hainan, Yunnan) or had more strict traffic control (e.g., Beijing). Furthermore, travelers to these provinces were more likely to be tourists as opposed to returning home; therefore, they have little social ties to the local population and are less likely to introduce widespread local transmissions.