As coronavirus cases surge across much of the United States, leaders are urgently rethinking their strategies to curb the spread, which the nation’s top infectious disease expert said on Friday were “not working.” For the first time, some governors are backtracking on reopening their states, issuing new restrictions for parts of the economy that had resumed.

Leaders in Texas and Florida abruptly set new restrictions on bars, a reversal that appeared unthinkable just days ago. And Gov. Gavin Newsom of California told rural Imperial County, where hospitals have been overwhelmed with patients, that it must reinstate a stay-at-home order, the most restrictive of requirements.

More than 45,000 new cases were reported on Friday in the United States, according to a New York Times database. It was the third day in a row that the country set a daily record during the pandemic. At least six states — Florida, Idaho, Kansas, Oregon, South Carolina and Utah — hit daily highs on Friday, but even leaders outside of the new hot zones in the South and West expressed mounting anxiety.