US coronavirus ventilator
File picture: A person wearing protective clothing and a respirator mask donates protective equipment to the Elmhurst Hospital Center in the Queens borough of New York, US, on Thursday, March 26, 2020. Image Credit: AP

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 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.

44,000 new cases

More than 44,000 new cases were reported 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 Friday, but even leaders outside of the new hot zones in the South and West expressed mounting anxiety.

"This is a very dangerous time," Gov. Mike DeWine of Ohio said Friday as cases were trending steadily upward in his state.

The stock market responded badly, with the S&P 500 dropping 2.4%. Losses accelerated after the Texas announcement, adding to investors' concerns that the virus continued to be a threat to the economy.

What Dr Anthony Fauci said

The shifting assessments of the nation's handling of the virus stretched to the highest levels of the federal government, where Dr. Anthony Fauci, the director of the National Institute of Allergy and Infectious Diseases, made clear that the standard approach to controlling infectious diseases - testing sick people, isolating them and tracing their contacts - was not working.

In a brief interview Friday, he said officials were having "intense discussions" about a possible shift to "pool testing," in which samples from many people are tested at once.

The renewed sense of urgency comes as the United States confronts a new, treacherous phase of the pandemic, no longer defined by a crisis concentrated in New York City, but by rising cases in many cities and states. Alabama, Alaska, California, Georgia, Missouri, Nevada, Oklahoma and Texas reported their highest single-day totals of new known cases this week, and the United States set records for daily new cases on both Wednesday and Thursday. By Friday, new daily cases were rising in 29 states.