Los Angeles County reported a new high for COVID-19 cases on Friday, topping the record set the day before.

There were 13,815 new cases reported on Friday, surpassing Thursday's record by nearly 1,000.

Los Angeles County Public Health Director Barbara Ferrer attributed the surge to Thanksgiving gatherings.

"The impact of these Thanksgiving surges of cases, on top of already rising cases, is creating extraordinary stress," she said at a briefing. "Should this be followed by another surge related to the winter holiday, the numbers of hospitalizations and patients in the ICU could become catastrophic."

There are 3,624 people currently hospitalized with COVID-19. In two weeks, that could be over 7,300 people, Ferrer warned, if the average number of cases and hospitalizations continue to climb.

-ABC News' Bonnie Mclean and Cammeron Parrish contributed to this report

The Department of Health and Human Services said it’s buying another 100 million doses of Moderna's vaccine candidate, which is scheduled for review by the FDA advisory committee next Thursday.

The federal government will now own a total 200 million doses of the Moderna vaccine.

ABC News’ Stephanie Ebbs contributed to this report.

In a Friday phone call, White House chief of staff Mark Meadows suggested to FDA Commissioner Stephen Hahn that his job could be on the line if his agency doesn't authorize emergency use of the Pfizer-BioNTech vaccine by the end of the day, sources familiar with the matter said.

"We don’t comment on private conversations, but the chief regularly requests updates on progress toward a vaccine," a White House official told ABC News.

Vaccine authorization by the FDA is expected imminently, as early as today.

ABC News’ Katherine Faulders and John Santucci contributed to this report.

Dr. Anthony Fauci told The New York Times that he'll “get vaccinated publicly, in the public space, so that people can see me getting vaccinated,” as soon as “the vaccine becomes available to me.”

Former Presidents Barack Obama, George Bush and Bill Clinton have all offered to get vaccinated on camera.

The Food and Drug Administration as early as today could authorize emergency use authorization for the Pfizer-BioNTech vaccine.

The chief science adviser to Operation Warp Speed, the U.S. government's initiative to expedite vaccine development, said he doesn't know what vaccine-related executive order President Donald Trump is expected to sign on Tuesday.

"Frankly, I don't know and, frankly, I'm staying out of this. I can't comment," Dr. Moncef Slaoui told ABC News chief anchor George Stephanopoulos in an interview Tuesday on "Good Morning America."

When pressed on the matter, Slaoui added: "Our work is, you know, rolling. We have plans. We feel that we can deliver the vaccines as needed, so I don't exactly [know] what this order is about."

Trump is expected to discuss the order at a COVID-19 vaccine summit to be held at the White House later Tuesday, multiple White House officials told reporters during a background briefing on Monday evening. While it's not entirely clear on how exactly the order would work, the move is designed to prevent the U.S. government from shipping any vaccine doses it has purchased to aid foreign countries until all the needs within the United States are met.

White House officials also denied reports that the Trump administration turned down an offer last summer to purchase an additional 400 million doses of a COVID-19 vaccine developed by U.S. pharmaceutical giant Pfizer and its German partner BioNTech, and that the companies now may not be able to provide more of their vaccine to the United States until June 2021 because they have committed those doses to other countries.

When asked about the matter, Slaoui explained Operation Warp Speed's strategy in securing vaccine doses.

"We selected six different vaccines to build a portfolio to manage the risk that some may work and some may not work, but also to ensure that as more than one would work that we would accumulate vaccine doses from this portfolio of vaccines," he said. "If somebody came to us and said, let's buy more of this vaccine or that vaccine, no one reasonably would buy more from any one of those vaccines because we didn't know which one would work and which one may be better than the other. Once the vaccine's performance becomes known is the right time, given the strategy we've taken, to go and order more vaccine doses, which we may be doing. And frankly, the constructive thing to do if one of the suppliers has challenges producing enough vaccine doses is to roll our sleeves and help ensure that capacity can be increased."

Slaoui said he's confident the U.S. government will be getting vaccines to Americans who need them "as soon as possible" and that plans are "still on track."

"We will work with Pfizer to try and increase capacity and have those vaccines available," he said. "We have two more vaccines from J&J and AstraZeneca that will be completing their Phase 3 trials in January and most likely, I hope, be approved for use in February. We have tens of millions of doses from those vaccines, you know, participating to the volume of vaccines we need to immunize the U.S. population as we promised, all of it by the middle of the year 2021 and that's still on track."

Slaoui said Operation Warp Speed has a meeting with President-elect Joe Biden's transition team scheduled for Thursday.

"We look forward to, you know, sharing all the information and working together," he said. "Our objective has always been outside of politics and making sure we make available these vaccines for the U.S. people, and that's what we're doing."

ABC News' Ben Gittleson, John Parkinson and Eric Strauss contributed to this report.