UK experts are set to recommend all 16 and 17-year-olds should be offered a Covid vaccine, the BBC has been told.
The Joint Committee on Vaccination and Immunisation stopped short of making the move last month, saying it was still assessing the benefits and risks.
About 1.4 million teenagers will be included in the new rollout but it is not known when the jabs will start.
They are only offered now to those over-12s who have underlying conditions or live with others at high risk.
But some countries, including the US, Canada and France, are routinely vaccinating people aged 12 years old and over.
Whitehall sources say ministers in England are expected to accept the advice of the JCVI, following an announcement on Wednesday.
It comes after Scotland’s First Minister Nicola Sturgeon said on Tuesday she was “hoping” to receive updated advice from the JCVI on the vaccination of 16 and 17-year-olds.
Ms Sturgeon said the UK’s four chief medical officers had written to the JCVI, asking them to look again at vaccination advice for young people.
Universities Minister Michelle Donelan said an announcement was “imminent and… people will get clarity soon”.
Meanwhile, new research suggested children who became ill with coronavirus mostly recovered within less than a week.
Across England, 223,755 under-18s have received a first vaccine dose, according to NHS data to 25 July.
It was previously announced that under-18s would be eligible if they had certain health conditions, lived with someone with a low immune system, or were approaching their 18th birthday.
But there was criticism after it emerged GPs were advised to hold off inviting clinically vulnerable 12 to 15-year-olds to take a vaccine due to uncertainty over insurance.
Decisions on vaccinations are based on recommendations from the independent JCVI. Ministers in England, Wales, Scotland and Northern Ireland each then approve the plans.
The only Covid jab currently authorised in the UK for under-18s is the Pfizer-BioNTech vaccine.
Last month, the JCVI extended its recommendation on Covid jabs to children aged over 12 who are at higher risk of getting ill and to those on the verge of turning 18.
However, it said it would not extend the rollout as it examined reports of rare adverse events such as inflammation of heart muscles among young adults.
Speaking ahead of the July decision, England’s chief medical officer Prof Chris Whitty said the JCVI was confident vaccines would protect children to a high degree.
He added more research was taking place as children did not tend to suffer severely from Covid, and the experts wanted to ensure the benefits of the jab outweighed any potential risks.