The acrimony is only likely to intensify in coming months as vaccine mandates take effect at hundreds of colleges and universities, following a federal judge’s refusal this week to block Indiana University’s mandate. The Food and Drug Administration also is expected to fully approve the vaccines by fall, which is expected to embolden more employers to require the shots.

Public health experts say they’re grappling with an irony: Americans who are already vaccinated tend to treat the coronavirus threat more seriously than many of the unvaccinated — even though the delta variant is poised to tear through populations that lack protection.

“We do know from our data that the vaccinated tend to be more worried about getting sick from covid than the unvaccinated,” said Mollyann Brodie, a Kaiser Family Foundation executive vice president who oversees the organization’s polling. “The reality, though, is that the new infections, hospitalizations and deaths are almost exclusively among the unvaccinated.”…

But even the exhortations of prominent Republicans have their limits. A new poll from the Associated Press-NORC Center for Public Affairs Research found that 80 percent of Americans who remain unvaccinated said they probably or definitely will not get the vaccine. The survey also found 64 percent of unvaccinated Americans have little-to-no confidence in the vaccines working against variants, despite evidence showing otherwise.