“We’ve lost the ability to corral this thing,” Dr. Thomas W. Eppes Jr. said he told Mr. Falwell. But he did not urge him to close the school. “I just am not going to be so presumptuous as to say, ‘This is what you should do and this is what you shouldn’t do,’” Dr. Eppes said in an interview.

So Mr. Falwell — a staunch ally of President Trump and an influential voice in the evangelical world — reopened the university last week, igniting a firestorm, epidemiologically and otherwise. As of Friday, Dr. Eppes said, nearly a dozen Liberty students were sick with symptoms that suggest Covid-19, the disease caused by the virus. Three were referred to local hospital centers for testing. Another eight were told to self-isolate.

“Liberty will be notifying the community as deemed appropriate and required by law,” Mr. Falwell said in an interview on Sunday when confronted with the numbers. He added that any student returning now to campus would be required to self-quarantine for 14 days.