After weeks of plunging U.S. Covid-19 cases, the decline in infections has stalled out.

New infections have dropped to an average of more than 74,000 per day over the past week, a 57% drop from the delta wave’s peak level of 172,500 new cases per day on Sept. 13.

While that surely is good news, the downward trajectory has leveled off in recent weeks, bouncing between 70,000 and 75,000 new cases a day for nearly three weeks, according to data compiled by Johns Hopkins University. Covid hotspots across the U.S., in the meantime, have shifted away from much of the South. ...