How Colleges Became the New Covid Hot Spots

But Alabama, whose Tuscaloosa campus has suffered one of the nation’s more significant college outbreaks, has not opted to repeatedly test the entire student population, unlike some other schools where the virus is spiking. Dr. Hanage cautioned that few campuses will make it through the semester with in-person classes without rigorous screening.

At the University of Dayton in Ohio, President Eric Spina said the school of 8,500 undergraduates launched an aggressive testing and tracing program after a meeting of students with too few masks caused a cluster of cases, followed by another outbreak in dense student housing on the campus periphery.

“We were caught off guard when cases started going from a few a day to 30 a day,” Mr. Spina said. A blitz of tests soon uncovered 100 cases a day, mostly asymptomatic. Only two students had to be hospitalized, and both have recovered.

“We are in a much better place than we were,” he said, noting that the university hopes to start in-person classes next week.

That level of testing, however, has been the exception. A group of faculty and students at the California Institute of Technology who in August analyzed reopening plans at some 500 universities around the country found that only 27 percent of schools planned to test undergraduates for the virus as they returned to campus, and only about 20 percent planned to do any regular screening.

An author of the study, Sina Booeshaghi, a Caltech graduate student, said that the extent of a campus’s testing program correlated strongly with the size of its endowment, indicating that cost was a factor. (Coronavirus tests can cost $100 or more per person.) Lior Pachter, a computational biologist at the university, said many schools had pushed responsibility for health and safety down to the individual student or faculty level.

At Miami University in Oxford, Ohio, officials said they had no plans to alter their existing protocol when dorms opened next week for 5,000 students, most of them freshmen. The school has recorded more than 1,174 cases since Aug. 17 — about half of those in the past week — even though classes started remotely and residence halls have been closed. The school plans to offer in-person classes starting Sept 21.