There will be test of this thesis in Poland soon. As government closed down universities, some of them told students that they have to vacate their dormitories and go back home (dormitories are usually occupied by students from countryside and smaller cities), and it caused massive migration. It is already confirmed that students in my city were infected for two weeks, but is not known yet how widespread it was. To make situation worse, some dormitories are now being turned into quarantine hotels, so students are told to come back and take their belongings with them (initially they were told they can leave their stuff behind).