States with rapidly expanding coronavirus outbreaks should seriously consider “shutting down” like the country did when the virus first hit the U.S. in March, White House health advisor Dr. Anthony Fauci said.

His comments Wednesday come as the U.S. continues to push records for new cases reported each day, driven primarily by states in the South and West, across the so-called Sun Belt.

“What we are seeing is exponential growth. It went from an average of about 20,000 to 40,000 and 50,000. That’s doubling. If you continue doubling, two times 50 is 100,” Fauci said on a Wall Street Journal podcast. “Any state that is having a serious problem, that state should seriously look at shutting down. It’s not for me to say because each state is different.”

On Thursday, however, Fauci said states should not necessarily think about it as a complete shutdown, according to the Hill, but rather that states should update their restrictions, tailoring them to what is currently known about the virus. 

“Rather than think in terms of reverting back down to a complete shutdown, I would think we need to get the states pausing in their opening process, looking at what did not work well and try to mitigate that,” Fauci, director of the National Institute of Allergy and Infectious Diseases, told The Hill’s Editor-at-Large Steve Clemons. “I don’t think we need to go back to an extreme of shutting down.”

Earlier this week, the U.S. reported a record single-day spike of 60,021 confirmed cases. Arizona, California, Florida and Texas have accounted for nearly half of all new cases in the U.S. in recent days.

The country has reported about 52,444 new cases per day on average over the past seven days, up 20.3% compared with a week ago, according to a CNBC analysis of data collected by Johns Hopkins University. The seven-day average has a hit a record high every day for the past two weeks, according to CNBC’s analysis.

Despite a major surge in Florida, Republican Gov. Ron DeSantis has previously said the state will not order businesses to close again. Though local officials in particularly hard-hit counties and cities might take matters into their own hands.

“We’re not going back, closing things. I don’t think that that’s really what’s driving it, people going to a business is not what’s driving it,” DeSantis said on June 30. “I think when you see the younger folks, I think a lot of it is more just social interactions, so that’s natural.”

The surge in cases across much of the U.S. has been driven by some states that reopened too early, said Fauci, director of the National Institute of Allergy and Infectious Diseases. He added that people who failed to practice public health guidance even if their state officials tried to encourage it have also driven the spread of the virus. 

Florida, for its part, was among the first states to reopen, with DeSantis allowing most restaurants and stores to open with modifications on May 4.

“Among the states, and there’s admission from within, some states went too fast, some states went according to what the timetable was, but the people in the state didn’t listen and just threw caution to the wind,” he said. “Some states, it gets frustrating, because, not to name any states, but some states admittedly opened up too early and too quickly, so that was something that probably should not have happened that led to this.”

Even as new cases have skyrocketed, the average age of an infected person has fallen in many states. That’s significant because younger and otherwise healthy people are less likely to become severely sick or die from Covid-19. However, Fauci said the more young people who are infected, the more likely they will pass the virus on to a vulnerable person who’s older or has an underlying condition that places them at greater risk of dying.

“To say that it’s benign is not true, because we’re already seeing the hospitalizations going up in these states,” he said. “We’re seeing the intensive care beds are now almost being fully occupied, so this is not inconsequential what’s going on. It’s having an impact.”

The seven-day average of hospitalizations rose by at least 5% in 25 states on Wednesday, according to a CNBC analysis of data compiled by the Covid Tracking Project, an independent volunteer organization launched by journalists at The Atlantic.

To get the outbreak under control, Fauci urged Americans to follow public health guidance and to take the threat of the virus seriously. He added that U.S. officials ought to better coordinate their messaging to more effectively reach the American people.

“Obviously, you’d like to see a consistent message all along that people understand,” he said. “But for better or worse, unfortunately, that’s not exactly what’s going on.”

— CNBC’s Nate Rattner contributed to this report.

Correction: States with rapidly expanding coronavirus outbreaks should seriously consider “shutting down,” White House health advisor Dr. Anthony Fauci said Wednesday. An earlier version misstated the day.