Passengers wearing protective face masks enter the departure hall of a high speed train station in Hong Kong, Friday, Jan. 24, 2020. Cutting off access to entire cities with millions of residents to stop a new virus outbreak is a step few countries other than China would consider, but it is made possible by the ruling Communist Party's extensive social controls and experience fighting the 2002-03 outbreak of SARS. (AP Photo/Achmad Ibrahim)