Cornell University, in upstate New York, welcomed around 24,000 people back to campus this fall. The idea of students packed into dorms and mingling in classrooms made many people nervous. But while outbreaks have plagued colleges across the country, Cornell has managed to keep a lid on its Covid cases. In fact, the college’s test-positivity rate has been among the lowest of any college or university in the country doing large-scale testing. Reporter Emma Court looked into how the school has done it.