Fig. 2

a Estimated median number of daily infected arrivals and b estimated cumulative number of infected arrivals from Wuhan for the four chosen cities (Beijing, Chongqing, Hangzhou, and Shenzhen, left to right) for Chunyun vs. non-Chunyun and cordon sanitaire imposed vs. no cordon sanitaire. The shaded area indicates the 95% uncertainty interval. The vertical dashed line indicates the date the cordon sanitaire was imposed