More than 25 million cases of coronavirus have now been confirmed across the United States.
A nurse cares for a patient in intensive care in a hospital in Chicago. (file pic) Photo: AFP / Northwestern Medicine
Experts say the true number is likely to be higher. More than 417,500 in the US have died with the virus.
The daily number of deaths has exceeded 4000 in recent weeks - including on Wednesday when Joe Biden was sworn into office.
President Biden signed a raft of new measures last week, including boosting vaccinations and testing.
He has implored Americans to wear masks and warned the death toll could get much worse.
"Let me be clear - things will continue to get worse before they get better," he said.
President Biden's efforts follow widespread criticism of the Trump administration's handling of the pandemic.
Joe Biden at work in the Oval Office is pleading with Americans to wear masks. Photo: AFP / Getty Images
How bad is the situation across the US?
Total cases went over 25 million on Sunday, according to tracking data from Johns Hopkins University.
Infections have spiralled in recent months - with a jump in new infections after Thanksgiving and Christmas, according to the Covid Tracking Project.
Hospital numbers hit their highest levels during the pandemic earlier this month but are slowly starting to drop alongside daily cases.
Dr Anthony Fauci, the top US infectious disease expert, said on Thursday that rolling average data appeared to show infections levelling off.
Although the national picture has stabilised slightly, he warned the country remained in a "very serious situation".
The Centre for Disease Control and Prevention (CDC) is particularly concerned that new variants could accelerate the virus spread.
It issued a warning that the new more transmissible strain first detected in the UK could become the dominant strain across the US by March.
The strain has been detected in 20 states, Dr Fauci said on Thursday, but warned the country had "limited ability" to track its spread through the population.
Call for urgent action on rescue plan
President Biden has already enacted a raft of executive measures to combat the virus and he wants Congress to pass a $US1.9 trillion package of economic relief funding.
The president is hoping to get bipartisan approval for his broad stimulus agenda, but the proposal has already been met with scepticism and resistance by some Republicans.
The director of the National Economic Council, Brian Deese, was expected to speak with a group of senators from both parties on Sunday about Biden's American Rescue Plan.
"If we don't act now, we will be in a much worse place, and we will find ourselves needing to do much more to dig out of a much deeper hole," Deese said of the need for economic action.
Another one of the new president's key promises is to oversee 100 million vaccinations in his first 100 days in office, but some have criticised this policy as not ambitious enough.
"When I announced it, you all said it's not possible," Biden said on Thursday when asked if his goal was high enough. "Come on, give me a break, man. It's a good start."
The CDC said 1.6m doses of Covid-19 vaccines had been administered on Friday alone, helping the US to top 20.5m doses given out in total.
Some 41.4m doses have been distributed so far, according to the CDC, but officials in some states have complained about supplies running low.
Vaccinations postponed in New York
New York City postponed 23,000 vaccination appointments last week due to a shipping delay, according to Mayor Bill de Blasio.
The current approved suppliers - Moderna and Pfizer - have pledged to deliver 200 million doses by March. Dr Fauci has also suggested emergency approval of a third vaccine, a single-dose jab by Johnson & Johnson, could be just weeks away.
A woman is vaccinated in Foxborough, Massachusetts. Photo: 2021 Getty Images
Dr Fauci, who was appointed chief medical adviser by the new president, has expressed hope that if 70-85 percent of the US population is vaccinated by the end of summer, the country could "approach a degree of normality" by autumn.
"It's not going to be perfectly normal, but one that I think will take a lot of pressure off the American public," he told a White House briefing.
President Biden's administration has also re-engaged with the World Health Organisation (WHO) and is joining its Covax programme to help ensure vaccine access worldwide.
The move was welcomed by WHO chief Dr Tedros Adhanom Ghebreyesus.
- BBC