The UK's healthcare regulator has approved Moderna's COVID-19 vaccine for use.
It is the third jab the country has approved as part of its vaccine programme along with those from Pfizer/BioNTech and AstraZeneca.
The UK has secured 17 million doses of the shot but they are not expected to be available until the spring.
The government said scientists from its Medicines and Healthcare products Regulatory Agency (MHRA) carried out a "thorough and rigorous assessment" along with the independent Commission on Human Medicines to ensure this vaccine meets the required standards of safety, quality and effectiveness to be used.
EU medicines regulator the European Medicines Agency (EMA) recommended authorising the vaccine, the second to receive its green light after Pfizer, on Wednesday.
The 27-nation bloc has ordered up to 160 million doses of the vaccine.
Like the Pfizer/BioNTech vaccine, the Moderna jab uses messenger RNA (mRNA) to instruct cells to make the coronavirus' spike protein.
But Moderna's shot is easier to handle than the Pfizer vaccine because it doesn't need to be stored at ultra-frozen temperatures.
The US first authorised use of the Moderna vaccine in December.
The UK intends to deploy hundreds of thousands of vaccines by next week and will inoculate 15 million people by February 15, Prime Minister Boris Johnson said on Thursday.
He told a televised press conference that the government planned to vaccinate people at nearly 1,500 locations around the country.
Vaccine supplies were “enough” for the country’s most vulnerable people, he added.
When asked about the UK's shift in strategy to prioritising giving one dose of the vaccine to as many at-risk people as possible, rather than providing the required two doses in as short a time as possible, he said: "If we had infinite vaccines, we might've taken a different approach."
The UK approval of the jab from the American biotechnology comes after it was reported one-in-50 people in England had COVID-19 last week, according to new figures cited by Johnson at a press conference on Tuesday.
The Office for National Statistics estimates 1.1 million people in England's private households had the virus between 27 December and 2 January.
On the same day, the country logged a new daily high for COVID cases - 60,916. It's the first time the total has exceeded 60,000.
A new nationwide lockdown took effect at midnight on Tuesday and comes at a complicated point during the pandemic with the UK grappling with a new variant of the virus.