Dr. Anthony Fauci on Monday said the US might never get entirely back to where it was before the coronavirus pandemic, especially without a vaccine.

"If you want to get back to pre-coronavirus, that might not ever happen in the sense that the threat is there," Fauci said, expressing optimism that new therapies and a vaccine would help the US recover.

Fauci said that with "the therapies that will be coming online, and the fact that I feel confident that over a period of time we will get a good vaccine, that we will never have to get back to where we are right now."

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In a Monday press briefing of the White House coronavirus task force, Dr. Anthony Fauci said the US might never get entirely back to where it was before the coronavirus pandemic, especially without a vaccine and effective treatments.

As of Monday, there were more than 364,000 confirmed cases of COVID-19, the disease caused by the novel coronavirus, in the US, with more than 9,600 deaths, according to data collected by Johns Hopkins University.

Both economic activity and life as normal have come to a grinding halt across the country. Forty-four states have issued some form of a stay-at-home order temporarily closing down nonessential businesses and telling citizens to practice social distancing and stay at home as much as possible to mitigate the spread.

And while some states have shown encouraging signs that widespread social distancing is working to slow the progression of the disease, US officials warn that social distancing and other mitigation measures remain crucial to help flatten the rate of new cases.

Fauci, the longtime director of the National Institute for Allergy and Infectious Diseases, is the nation's top infectious-disease expert.

At the briefing, the ABC News correspondent Jon Karl said, "you said you wanted to get back to normal as soon as possible," asking, "Will we truly get back to normal in this country before there's an actual vaccine that's available to everybody, and how do you start lifting the restrictions without a vaccine?"

"If 'back to normal' means acting like there never was a coronavirus problem, I don't think that's going to happen until we do have a situation where you can completely protect the population," Fauci said. "But when we say getting back to normal, we mean something very different from what we're going through right now. Because right now, we're in a very intense mitigation.

"When we get back to normal, we will go back to the point where we can function as a society. But you're absolutely right. If you want to get back to pre-coronavirus, that might not ever happen in the sense that the threat is there. But I believe that with the therapies that will be coming online, and the fact that I feel confident that over a period of time we will get a good vaccine, that we will never have to get back to where we are right now."

Fauci emphasized that "you never even think about claiming victory prematurely." He said, however, that New York reporting a leveling off in hospitalizations and an increase in daily hospital discharges showed that mitigatory measures like social distancing were working, and he encouraged states to "keep it up."

Several clinical trials are underway, testing both therapies to treat COVID-19 patients and vaccines that could protect against contracting the disease.

On Monday, Inovio Pharmaceuticals began clinical trials in both Philadelphia and Kansas City, Missouri, for an experimental coronavirus vaccine backed by the Bill & Melinda Gates Foundation. Other trials are testing the effectiveness of drugs such as the anti-arthritis drug Actemra and the antimalarial hydroxychloroquine as therapies for COVID-19.

In March 11 testimony before the House oversight committee, Fauci said that while researchers were working quickly to develop a vaccine across multiple trials in different stages, he estimated that a "deployable vaccine" would not be available for at least a year to a year and a half.

He said reaching a phase-one clinical trial in a matter of months was "the quickest that anyone has ever done literally in the history of vaccinology," continuing: "But the process of developing a vaccine is one that is not that quick. It will bring us three or four months down the pike, and then you go into an important phase called phase two to determine if it works. That will take at least another eight months or so."