Post-infection immunity was very protective against Delta, the C.D.C. reports, but vaccines still offer the best defense.
Starbucks baristas in training in Cheektowaga, N.Y. The company said the vast majority of its workers were vaccinated.Credit…Libby March for The New York Times The Supreme Court’s ruling last week shutting down the Biden administration’s effort to enlist large employers in its vaccination campaign, experts said, would trigger a new wave of uncertainty about how…