More than 213,830 new cases and 2861 deaths were reported on Thursday, according to a Reuters tally of official data.

With US COVID-19 hospitalisations also at record levels, several experts project the death toll will soon surpass 3000 per day.

President-elect Joe Biden promised a new national strategy that will impose mask mandates where he will have authority, such as federal buildings and for interstate travel, once he takes over for departing President Donald Trump on January 20.

Beyond the mandate, he urged people to voluntarily wear masks, seeking to counter lax public discipline to date and Trump's own timid endorsement of mask-wearing.

"On the first day I'm inaugurated ... I'm going to ask the public for 100 days to mask, just 100 days to mask, not forever, 100 days," Biden told CNN on Thursday.

"And I think we'll see a significant reduction if we incur that - if that occurs, with vaccinations and masking, to drive down the numbers considerably."

Two promising vaccines could soon receive emergency use authorisation from the US Food and Drug Administration, and some 20 million Americans could be vaccinated this year, FDA Commissioner Stephen Hahn said on Friday.

As soon as the FDA approves a vaccine, "I will be first in line and I will encourage my family to take this vaccine", Hahn said.

Biden said he would be happy to get vaccinated publicly, as former presidents Bill Clinton, George W Bush and Barack Obama have pledged, in order to boost public confidence and persuade vaccine sceptics.

Other public figures have followed, including best-selling novelist Stephen King.

"As a kid of 5 or 6, I lined up with other little people to get the Polio Vaccine. As a man of 73, I'll line up for the Covid Vaccine as soon as I'm told it's time," King said on Twitter.

The US government's first shipment of millions of coronavirus vaccine doses is expected to be shared by states and federal agencies, including the Department of Defense.

But it will fall far short of protecting high priority groups such as healthcare workers, a Reuters analysis has found.

Anthony Fauci, a member of the White House coronavirus task force, said on Friday he expected to see another surge in infections two or three weeks after the November 26 Thanksgiving holiday.

"We really have to intensify our public health measures," he said.

Fauci also said he has accepted Biden's offer to be his chief medical adviser, as well as keep his current position.

US cases since the start of the pandemic surpassed 14 million on Thursday and more than 100,000 people were hospitalised.

California Governor Gavin Newsom said he would impose strict new stay-at-home orders to be triggered on a region-by-region basis when less than 15 per cent of intensive care unit capacity is available.

Australian Associated Press