May 8, 2021, 5:00 a.m. ET
It first emerged as a sign — on faces in airports, at hospitals, on the streets — that this virus was not to be taken lightly.
Now, after 14 months of reliance on the mask for protection, its twilight appears to be in sight in certain parts of the world. In late April, the Centers for Disease Control and Prevention released new guidelines stating that fully vaccinated people no longer need to wear masks outdoors unless they are in crowds. Already, the C.D.C. had said that small groups of fully vaccinated people — more than 1.2 billion doses have been administered worldwide — could safely gather indoors unmasked.