The Moderna coronavirus vaccine has been authorised for people in the UK aged between 12 and 17, regulators announced today.
The decision by the Medicines and Healthcare products Regulatory Agency (MHRA) means the jab could now be offered to teenagers.
The next step is for the Joint Committee on Vaccination and Immunisation to advise the Government on whether children in this age group should be given the Moderna jab.
The Department of Health has formally asked the JCVI for a recommendation on whether to do so.
It is the second vaccine to be approved for use in UK under-18s after Pfizer.
The breakthrough seems unlikely to speed up the rollout for 12-to-17-year-olds already lined up for a jab, because they have been promised a first dose by Monday next week.
However, it will ramp up the debate over whether all over-12s should be offered a jab - not just those in selected groups.
Currently, all 16- and 17-year-olds are being offered a vaccine.
However, those aged 12 to 15 are only being offered a jab in certain groups - for instance, if they are clinically vulnerable to COVID-19, or who live with adults who are at risk of serious illness.
Last month the Joint Committee on Vaccination and Immunisation (JCVI) decided to not yet expand vaccinations to otherwise well under-18s because of concerns about a tiny number of cases of heart inflammation in children.
This position was being reviewed over the past month.
A spokesperson for the department said: "We welcome the news that Moderna's vaccine has been approved as safe and effective for people aged 12 and over.
"As has been the case with all other approvals, we will now be guided by the independent Joint Committee on Vaccination and Immunisation (JCVI) and have asked for its formal recommendation on whether to administer this vaccine to people aged 12 to 17.
"All young people aged 16 to 17, clinically vulnerable children aged 12 to 15 and people who live with adults who are immunosuppressed will be offered a first dose of a Pfizer jab by Monday 23 August."
Dr June Raine, MHRA chief executive, said: "I am pleased to confirm that that the Covid-19 vaccine made by Moderna has now been authorised in 12 to 17-year-olds. The vaccine is safe and effective in this age group.
"We have in place a comprehensive safety surveillance strategy for monitoring the safety of all UK-approved Covid-19 vaccines and this surveillance will include the 12 to 17-year age group.
"It is for the Joint Committee on Vaccination and Immunisation (JCVI) to advise on whether this age group should be vaccinated with the Covid-19 vaccine made by Moderna as part of the deployment programme."
