The nation's top infectious disease expert said Sunday that the U.S. may see "surge upon a surge" of the coronavirus in the weeks after Thanksgiving, and he does not expect current recommendations around social distancing to be relaxed before Christmas.

Meanwhile, in a major reversal, New York City Mayor Bill DeBlasio said the nation's largest school system will reopen to in-person learning and increase the number of days a week many children attend class. The announcement came just 11 days after the Democratic mayor said schools would shut down because of rising COVID-19 cases.

"We feel confi...