Fauci, the director of the National Institute of Allergy and Infectious Diseases, said if more people aren’t persuaded to get vaccinated by messaging from health officials and “trusted political messengers,” additional mandates from schools and businesses may be necessary.

“I believe that’s going to turn this around because I don’t think people are going to want to not go to work or not go to college … They’re going to do it,” Fauci told CNN’s Jen Christensen during an interview at the NLGJA, the Association of LGBTQ Journalists, convention Sunday. “You’d like to have them do it on a totally voluntary basis, but if that doesn’t work, you’ve got to go to the alternatives.”

The combination of the highly contagious Delta variant and the vaccine holdouts has put the United States in a “very difficult period” of the Covid-19 pandemic, Fauci said.