London: Britain approved Pfizer's COVID-19 vaccine on Wednesday, jumping ahead of the rest of the world in the race to begin the most crucial mass inoculation programme in history with a shot tested in wide-scale clinical trials.

Prime Minister Boris Johnson touted the green light from Britain's medicine authority as a global win and a ray of hope amid a pandemic, though he recognised the logistical challenges of vaccinating an entire country of 67 million.

Britain's move raised hopes that the tide could soon turn against a virus that has killed nearly 1.5 million people globally, hammered the world economy and upended normal life for billions since it emerged in Wuhan, China close to a year ago.

Britain's Medicines and Healthcare products Regulatory Agency (MHRA) granted emergency use approval to the vaccine developed by Pfizer and German biotechnology partner BioNTech, which they say is 95% effective in preventing illness, just 23 days after Pfizer published the first data from its final stage clinical trial.

"Fantastic news," Johnson told parliament, though he cautioned that people should not get carried away.

"At this stage it is very, very important that people do not get their hopes up too soon about the speed with which we will be able to roll out this vaccine."

The world's big powers have been racing for a vaccine for months to begin the long road to recovery from the pandemic, and getting there first may be seen as a coup for a government has faced criticism over its handling of the crisis.

UK in the lead

Both the United States and the European Union's regulator are sifting through the same Pfizer vaccine trial data, but have not yet given their approval.

Britain's breakneck speed drew criticism from Brussels where, in an unusually blunt statement, the EU's drugs regulator said its longer procedure was more appropriate as it was based on more evidence and required more checks.

Johnson might be persuaded to take a COVID-19 jab on television to show it was safe, but he would not have one before those in greater need, his press secretary said.

Just hours after the British announcement, President Vladimir Putin ordered Russian authorities to begin mass voluntary vaccinations next week. Russia will have produced 2 million does of its own vaccine within the next few days, Putin said.

Pfizer vaccine executive Ralf Rene Reinert said other countries were looking to emulate Britain.

"I wouldn't make this a race between countries," he said. "The UK is leading, and now let's see how the other countries move forward. And Pfizer will do everything to exchange all the data packages with every regulatory agency."

Germany's health minister Jens Spahn said EU member states could have issued similar emergency approvals but Europe had decided to move forward as one.

"It's very important we do this to help promote trust and confidence in this authorisation," he said.

'No corners cut'

Britain's medicines regulator approved the vaccine in record time by doing a "rolling" concurrent analysis of data and the manufacturing process while Pfizer raced to conclude trials.

"No corners have been cut," MHRA chief June Raine said in a televised briefing from Downing Street, adding that the first data on the vaccine had been received in June and undergone a rigorous analysis to international standards. "Safety is our watchword."

The emergency use approval does not come with any associated volume cap or threshold, Pfizer said.

"With 450 people dying of COVID-19 infection every day in the UK, the benefits of rapid vaccine approval outweigh the potential risks," said Andrew Hill, senior visiting research fellow in the Department of Pharmacology at the University of Liverpool.

The US Food and Drug Administration (FDA) will make a decision on emergency use authorization on the Pfizer/BioNTech vaccine in days or weeks after a panel of outside advisors meets on Dec. 10 to discuss whether to recommend it. The FDA often but not always follows the panel's advice.

The European Medicines Agency (EMA) said it could give emergency approval for the shot by Dec. 29.

"The data submitted to regulatory agencies around the world are the result of a scientifically rigorous and highly ethical research and development programme," said Ugur Sahin, chief executive and co-founder of BioNTech.

BioNTech said it expected FDA and EMA to make a decision in mid-December.

First in line?

Britain said it would start vaccinating those most at risk of dying early next week after it gets 800,000 doses from Pfizer's manufacturing centre in Belgium.

"I strongly urge people to take up the vaccine but it is no part of our culture or our ambition in this country to make vaccines mandatory," Johnson said.

The speed of the rollout depends on how fast Pfizer can manufacture and deliver the vaccine - and the extreme temperature of -70C (-94F) at which the vaccine must be stored.

Britain has ordered 40 million doses of the Pfizer vaccine - enough for just under a third of the population as two shots are needed per person to gain immunity.

Health Secretary Matt Hancock said hospitals were ready to receive the shots and vaccination centres would be set up across the country, but he admitted distribution would be a challenge given storage at temperature typical of an Antarctic winter.