Fig. 2

Inclusion and exclusion of student residences and contacts during the study period. We included all students residing in the same residence as a newly diagnosed index case as contacts if they met the above criteria for further testing. We excluded contacts who were lost to follow up and who were already diagnosed with COVID-19 between 14 and 60 days before the diagnosis of the index. We also excluded contacts that had not resided in their residence in the week leading up to the onset of symptoms or diagnosis of the first case