Association of University Student Gatherings With Community COVID-19 Infections Before and After the NCAA March Madness Tournament

Universities across the US are weighing various vaccination policies for the current fall semester.¹ It is difficult to assess the risk of social gatherings on university campuses among unvaccinated students. However, the NCAA Men’s Division I Basketball Tournament (March Madness) provides an opportunity to study this risk. In mid-March 2021, when variants were spreading rapidly² and vaccination rates were low among the college-aged population,³ 64 universities across the country competed in March Madness. By the event’s nature as a single-elimination tournament, it is difficult to predict which universities will proceed to the later rounds of the tournament. This cross-sectional study uses a difference-in-differences analysis to estimate the association of large celebrations at universities across the US with COVID-19 infections in a university’s county during a time of low vaccination rates among university students.