Dr. Anthony Fauci appeared on ABC News Live Wednesday and shared his thoughts on the U.S. Centers for Disease Control and Prevention's decision to lower its recommended isolation period to five days for asymptomatic patients.

Fauci also said that while new evidence shows  omicron may be less severe than delta, people should still be cautious of contracting and spreading the virus.

"You can get people safely back out in a five day period so long as they wear a mask, if they are without symptoms. That is the science," he told ABC News Live. "The impact of that is to try and not be in a situation where we essentially have to shut down the entire country."

Fauci also said it would be too premature to be less worried based on evidence that omicron may be less severe.

"We are heartened by the fact that from the South African data, the data from the U.K., and the accumulating data in the United States that it looks like it is less severe," he said. "It's much more transmissible, which is something you need to take seriously."

The U.S. Food and Drug Administration gave emergency use authorization to two over-the-counter COVID-19 tests.

The tests are manufactured by SD Biosensor and Siemens.

"Combined, it is estimated the companies can produce tens of millions of tests per month for use in the U.S.," the U.S. Department of Health and Human Services said in a statement.

-ABC News' Sony Salzman

The U.S. reported more than 1.9 million new cases this week, which equals about three Americans testing positive for COVID-19 every second.

The U.S. is now averaging 277,000 new cases each day, shattering the previous record average from Jan. 11, 2021, which was 250,000 cases each day, according to federal data.

Although this significantly high number is in large part due to the latest surge, it’s also attributable to the soaring demand for tests and backlogs of data following Christmas weekend.

-ABC News' Arielle Mitropoulos

In New York City, 30% of emergency medical workers and 17% of firefighters are out on leave tied to COVID-19 -- and the fire department is reminding New Yorkers to only call 911 in a true emergency.

"If you are not severely ill, allow first responders to assist those most in need," the FDNY said in a video message.

Meanwhile, the New York Police Department has canceled regular days off for Dec. 31 and Jan. 1 due to COVID-19 and staffing needs for New Year's Eve.

-ABC News' Mark Crudele, Aaron Katersky

The surge in COVID-19 cases is "going to get worse before it gets better, that's for sure," Dr. Anthony Fauci said Monday on "Good Morning America."

And it could take weeks for the number of daily cases to start declining, he noted.

"It's very difficult to predict, because we have so many unvaccinated people in this country who are really quite vulnerable," Fauci said. "Even with the vaccinated people, you're going to see breakthrough infections."

Fauci also sought to ease concerns about the availability of at-home tests. Demand for those tests spiked during the holiday season, as worries about omicron grew and families took precautions before gathering.

"Well certainly omicron is a very, very unusual variant in its incredible degree of spreading," Fauci said. "As we enter January, there will be many, many more tests that we have."