Businesses and colleges should consider requiring people to get vaccinated against COVID-19 in light of the surge of U.S. cases driven by the delta variant, top infectious disease expert Dr. Anthony Fauci said today.

The chief medical adviser to President Joe Biden said he opposed a federal vaccine mandate but that the velocity of COVID’s spread should spur private organizations to think about requiring shots.

“I would encourage private enterprises to seriously consider the idea of mandating vaccination in the enterprise for which they are responsible, whether that’s a university or a place of business,” Fauci said in an interview with Bloomberg Quicktake.

With the delta variant driving about 90,000 new COVID diagnoses a day in the U.S., private companies are increasingly making immunization a prerequisite for working on-site or patronizing public businesses.

United Airlines Holdings Inc. today became the first major U.S. airline to require workers to be vaccinated. New York City diners and theater patrons soon will have to show proof of vaccination.

Fauci said more companies should consider similar rules.

“We need to do whatever we can,” he said. “I know people don’t like mandates for them to do things that they feel encroach upon their individual liberty. But in fact, when you are in a public health crisis, sometimes you’ve got to look out for the good of the community as well as your own personal libertarian views.”