The US has authorised its first coronavirus vaccine for emergency use – but the nation's path to herd immunity against the deadly disease won't be an easy one.
The Covid-19 vaccine will begin arriving in states Monday morning, as Pfizer's vaccine is delivered to nearly 150 distribution centres across the states.
President-elect Joe Biden promised this week to vaccinate 100 million Americans in his first 100 days in the White House.
The US hopes to vaccinate 20 million people this month, with long-term care facility residents and health workers at the front of the line.
However, Biden warned that coronavirus vaccination efforts in the United States will "slow and stall" if Congress does not urgently come up with funding.
He stressed it was imperative for politicians to "finish the bipartisan work underway now or millions of Americans may wait months longer to get the vaccine".
America's floundering efforts to quell the pandemic have been widely criticised – the nation is the world's worst-hit, with more than 15 million cases and a death toll inching closer to 300,000 every day.
The US is now losing more than 3000 people a day to coronavirus with the nation's hospitals and support services stretched thin.
"I think we're past the breaking point," Dr Adolphe Edward, CEO of El Centro Regional Medical Center in Southern California, told CNN earlier this week.
"The staff is here, but they're broken.
"The resiliency starts to break down at some point, regardless of how much I know that this team is willing to do."
Dr Edward said the hospital had two beds left in intensive care, after that patients would be cared for in a pop-up field hospital, built in the carpark.
"I might really be back in a war zone," he said, comparing the field hospital to his time serving in the US military in the Middle East.
"We're at war against Covid."
US health officials warned of a surge after millions of Americans travelled to celebrate the Thanksgiving holiday despite pleas from authorities to stay home.
States continue to order their own lockdowns, however cases and deaths continue to rise.
California ordered most offices to close and banned gatherings among different households. Bars and services such as hair salons were shut, and restaurants were allowed to serve takeaway only.
Non-essential travel was also temporarily restricted statewide as California experienced record new Covid-19 cases.
The lockdown came as California Governor Gavin Newsom warned the state's hospital system risked being "overwhelmed."
The US Food and Drug Administration on Tuesday said data from trials of Pfizer-BioNTech drug revealed "no specific safety concerns", clearing the way for the organisation to authorise it for emergency use.
But health officials are at pains to get Americans to embrace other public health measures.
"This is not just the worst public health event. This is the worst event that this country will face," co-ordinator of the White House coronavirus task force Deborah Birx told NBC's Meet the Press.
"The vaccine is critical but it's not going to save us from this current surge."
Former FDA commissioner Scott Gottlieb predicted the US death toll, now more than 280,000, could hit 400,000 by late January.
"There is a grim future ahead of us for the next six weeks," he told CBS's Face the Nation.
"People really need to protect themselves."
And in a worrying turn of events, multiple recent polls indicate many Americans are still unsure whether they will choose to be vaccinated, while others have flat-out refused to ever get the jab.
A recent poll conducted by AP-NORC asked 1117 American adults whether they planned to get vaccinated when a Covid-19 vaccine becomes available.
The results, released on Wednesday, show just 47 per cent of respondents said they would get vaccinated against the virus.
Of the other respondents, 26 per cent said they wouldn't get the vaccine and 27 per cent said they weren't sure.
With many experts saying roughly 70 per cent of the population would need to be vaccinated against the virus to achieve herd immunity, that last category of undecided people becomes crucial.
General rollout of the vaccine in the US is expected around February with nursing home residents, staff and high-risk hospital workers likely being vaccinated before the end of this year as a priority.
The virus has killed more than 1.5 million people worldwide since the outbreak emerged in China last December, according to an AFP tally from official sources.
– With Wires