After years of modeling strict precautions, including campaigning for months from his basement in Wilmington, Del., before vaccines were available, Biden is now at a higher risk of being infected, experts say, with all the personal and political consequences that would entail — though as with other vaccinated people, an infection could be less severe.

“There’s very little doubt that the president could contract covid-19,” said Lawrence Gostin, faculty director of the O’Neill Institute for National & Global Health Law at Georgetown Law, who is in regular touch with Biden’s covid-prevention team.

The 79-year-old Biden’s vaccination status could help the president avoid serious infection, he said. “But even that is in doubt, given his age and obvious frailty,” Gostin added. “I would be far more worried about the president’s health than it appears from recent White House protocols.”