Covid cases in U.S. fall to levels not seen since March 2020

Confirmed coronavirus cases in the United States have fallen to levels not seen since March 2020, according to an NBC News analysis — and experts say they expect case counts to stay low through the summer.

Cases first surged in March last year, driven by a wave in New York City. That first surge peaked in April, then gradually decreased to a seven-day average of 19,000 cases June 1, 2020 — and would not fall below that threshold for the next year. On Wednesday, the seven-day average was 16,860, the lowest since...