Britain became the first Western country to start a mass coronavirus vaccine campaign with a pensioner receiving the initial jab on Tuesday as across the Atlantic millions of Californians went into lockdown to stop surging US infections.

Medical personnel prepare to administer the Pfizer-BioNTech Covid-19 vaccine to recipients at a health centre in Cardiff, South Wales' on December 8, 2020. (Photo: AFP)

The UK's rollout of the Pfizer-BioNTech jab -- the first country to start using the approved inoculations -- is one of several vaccines bringing hope for an end to the pandemic that has killed more than 1.5 million people worldwide and ravaged economies since late last year.

British pensioner Margaret Keenan, 90, said she felt "privileged" to be given the injection, the first of millions expected to be administered over the coming months in one of the world's worst-hit countries.

"My advice to anyone offered the vaccine is to take it," said Keenan, wearing a mask and a penguin T-shirt. "If I can have it at 90 then you can have it too."

British officials hailed the Pfizer-BioNTech jab as a turning point in the fight against the pandemic, and on what has been dubbed "V-Day", people rolled up their sleeves for an initial dose from early Tuesday morning.

The UK's second jab reportedly went to a man named William Shakespeare. The over-80s, care home workers, and at-risk health and social care staff will be at the front of the line.

The British public has been largely supportive of the rapid approval of the vaccine, but ministers and health professionals are aware they still need to combat mistrust over treatments that risks hampering global efforts to fight the disease.

Russia on Saturday began vaccinating high-risk workers with its own jab and Beijing has also begun an emergency inoculation campaign with a medicine made in China.

Britain's start to its vaccinations came as around the world the virus picture darkens, with more countries reimposing curbs and around 30 million people in California placed under stay-at-home orders to fight a deepening US crisis.

While the World Health Organization has warned that successful vaccines on their own will not immediately end the crisis, nations around the world are seeking safe candidates to administer to populations growing increasingly weary of restrictions and economic pain they cause.