Seven mass coronavirus vaccination sites opened across England Monday as the government raced to dose millions of people while a new strain of the disease runs rampant across the country.
Sites include football stadiums and a horse racing course and are located in cities including Bristol, London, Newcastle, and Manchester.
They are to vaccinate thousands per week with several more sites expected to follow, according to the National Health Service (NHS) in England.
"I feel very relieved," said Moira Edwards, 88, after receiving her first vaccination at Epsom Downs Racecourse, south of London, which is more famous for the Derby.
"I feel this is the way back. I can't understand anybody not wanting to have it."
The mainly elderly recipients of the jab, some of whom used walkers, sticks or were pushed in wheelchairs to get to the centre, were given "I've had my Covid vaccination" stickers.
Hospitals and pharmacies are set to begin offering the vaccine later this week, and the government hopes to have doses available for 12 million of England's 56 million population by mid-February.
A further three million are being targeted by the same date in Wales, Scotland, and Northern Ireland.
Priority is being given to the elderly, care home residents and workers, the clinically extremely vulnerable, and health and social care staff.
Some 2.4 million people have already been vaccinated across the UK since the roll-out began of the Pfizer-BioNTech jab on December 8, Prime Minister Boris Johnson said on a visit to Bristol.
That includes 40 percent of the over-80s, and nearly a quarter of elderly care home residents, he added, calling it a "race against time" as cases blamed on the new variant surge.
Britain has now also approved the Oxford-AstraZeneca and Moderna jabs, and drafted in logistics experts from the army to assist the inoculation drive.
Britain is grappling with its worst outbreak of the disease since it arrived early last year.
The record case rates and daily death toll are being blamed on a new, more contagious strain, which has piled pressure on the NHS, leading to warnings of shortages of critical care beds.
The state-run NHS risks being overwhelmed and the country is in its third lockdown until at least mid-February, with predictions the restrictions could last even longer.
In Northern Ireland, health chiefs said the province's hospitals were under intense pressure, and two health trusts had to draft in off-duty staff to alleviate pressure due the spike in cases.
"The next few weeks are going to be the worst weeks of this pandemic in terms of numbers into the NHS," England's chief medical officer Chris Whitty told BBC television on Monday.
"What we need to do, before the vaccines have had their effect… is we need to really double down" on observing lockdown measures, he added.
Britain on Saturday said it had recorded over three million coronavirus cases since the pandemic began last year.
On Friday, it reported a record of 1,325 deaths over a 24-hour period of people who tested positive for the virus, with fears that the fatalities could remain consistently high for weeks.
The full death toll now stands at more than 80,000, the highest in Europe.
At Leatherhead, near Epsom, bodies were being stored in a temporary 1,400-capacity mortuary because there was no space at local hospitals.
Lockdown rules include school closures but the government has been criticised for not going further, with evidence of continued close-contact mixing. The government does not require people to wear masks outside.
But Johnson said that although the rules were kept under review, adherence to existing guidelines would make a "huge, huge difference" to cutting infection rates.
He warned against "false confidence (and) false complacency" because of the vaccine roll-out, which aims to reach all adults by the end of October.
Britain was at a "very perilous moment", he said. "Now is the moment for maximum vigilance, maximum observation, observance of the rules."