A "huge vaccine rollout plan" is already in place across the NHS, with the health service ready to start immunising the most vulnerable to coronavirus as soon as December, the health secretary has said.
No vaccine will be deployed until the government is "confident it is clinically safe", Matt Hancock told ITV News, but whenever that is "we will be ready".
He said: "I've been working with the NHS for months to make this happen and we're working with GPs...to make sure that we can rollout a vaccine as quickly as it can be manufactured."
Mr Hancock added that there are no plans to make vaccine uptake compulsory, but he's "confident" that the number of people wanting to be vaccinated will be "really high".
He added: "This is a promising step forward, there's lots more steps to come but no matter when a vaccine comes, as soon as one is available, we will be ready."
Priority for the vaccine will first be given to those in care homes, the elderly and health and social care staff - a full priority list can be found here.
Professor Jonathan Van-Tam, England's deputy chief medical officer, said at a Downing Street press conference on Monday that he's "hopeful we could see some vaccine by Christmas" but he urged people to not "get too over excited about where we are".
Prime Minister Boris Johnson said initial results suggested the vaccine was 90% effective at protecting people from Covid-19 but warned these were “very, very early days”.
The announcement from Pfizer and its vaccine partner BioNTech was hailed by scientists as a significant breakthrough in the fight against coronavirus, while stock markets rallied on the news with the FTSE 100 jumping more than 5.5%.
It came with England less than a week into Lockdown 2.0, while Wales eased up from a firebreak lockdown on Monday.
Dr Richard Vautrey, chairman of the British Medical Association’s GP committee in England said practices would “stand ready” to deliver the vaccine, with clinics potentially running from 8am-8pm, seven days a week.
Deputy chief medical officer Professor Jonathan Van-Tam told a Downing Street press conference he was “hopeful” there would be “some vaccine by Christmas”.
He said: “Frankly, we’re in the middle of the second wave, and I don’t see the vaccine making any difference for the wave we are now in.
“I’m hopeful that it may prevent future waves, but this one we have to battle through to the end without a vaccine.
“This is a very important scientific breakthrough. I am certain of that.
“I am hopeful because of all that, but not yet certain that we could begin to see some vaccine by Christmas.”
Meanwhile, Baroness Harding, the head of the Test and Trace programme, is due to be quizzed by MPs on Tuesday. It comes after more than 40% of close contacts of people who tested positive in England were not contacted through the system in the week ending October 28.
And President Donald Trump claimed Pfizer announced the vaccine after the US election as they did not “have the courage to do it before”, tweeting: “The @US_FDA (Food and Drug Administration) and the Democrats didn’t want to have me get a Vaccine WIN, prior to the election, so instead it came out five days later – As I’ve said all along!”
The UK Government has ordered 40 million doses of the Pfizer vaccine – enough for about a third of the UK population.
But Mr Johnson said it would be a mistake to “slacken our resolve at such a critical moment”.
Government figures show 49,238 people have died in the UK within 28 days of testing positive for Covid-19 and the number of cases has reached 1,213,363.
Mr Johnson said: “The Pfizer/BioNTech Vaccine has been tested on over 40,000 volunteers and interim results suggest it is proving 90% effective at protecting people against the virus.
“But we haven’t yet seen the full safety data, and these findings also need to be peer-reviewed.
“So we have cleared one significant hurdle but there are several more to go before we know the vaccine can be used.”
Data released about the Pfizer/BioNTech vaccine does not indicate how long immunity lasts, but suggests protection is achieved 28 days after vaccination.
It is also not yet known how well the vaccine works in the most high risk, elderly people.
Other experts have said that should a vaccine become available early next year, it may take more than a year for everyone in the UK to be immunised against Covid-19.