All 16 and 17-year-olds in the UK should be offered a first dose of the Covid jab, the UK's vaccine experts have recommended.
England, Wales and Northern Ireland have already confirmed they will expand their rollout, and Scotland is expected to do so.
Advice on when to offer the second dose will come later, the Joint Committee on Vaccination and Immunisation said.
The change in guidance means around 1.4 million teenagers will be eligible.
Prof Jonathan Van-Tam, England's deputy chief medical officer, said he expected the programme would start in "a very short number of weeks".
"There is no time to waste in getting on with this," he said. "I want us to proceed as fast as is practically possible."
The JCVI is a group of independent experts and their advice is a recommendation. It is then up to the governments of England, Scotland, Wales and Northern Ireland to put it into action.
Up until now, children over 12 are able to get a jab if they have certain health conditions, live with others who are at a high risk or are nearing their 18th birthday.
The only vaccine approved for those under-18 in the UK is Pfizer-BioNTech.
Some other countries have already been routinely vaccinating children over 12. The US has been doing so from May, as well as some European countries like France and Italy, after the EU gave them the go-ahead. Other countries that are vaccinating children include Brazil, Japan, Israel and Hong Kong.
Last month, the JCVI stopped short of opening up jabs to 16 and 17-year-olds as it wanted time to examine the risks and benefits, as well as reports of rare adverse effects such as inflammation of heart muscles.
The JCVI said earlier: "These are extremely rare and usually occur within a few days of the second dose, typically more in young men.
"Data from the USA suggests that, in males aged 12 to 17 years, 9.8 cases of myocarditis were reported per million first doses given. This rises to 67 per million after the second dose. Most people recovered quickly."
The JCVI said it expected one dose of the vaccine to give good protection against severe illness and hospitalisation in the 16 and 17 age group.
Prof Wei Shen Lim, who chairs the Covid part of the JCVI, said the change in advice wasn't just for the benefits to wider society. "Vaccination of children and young people can bring benefits to other people, such as adults and including parents and grandparents but, at the forefront, is the health and the benefits to children and young people themselves," he said.
Health Secretary Sajid Javid said he had asked the NHS in England to prepare to vaccinate those eligible "as soon as possible".
"The JCVI have not recommended vaccinating under-16s without underlying health conditions but will keep its position under review based on the latest data."
Covid: Jabs for 16 and 17-year-olds to start 'within weeks' - BBC News
England, Wales and Northern Ireland have already confirmed they will expand their rollout, and Scotland is expected to do so.
Advice on when to offer the second dose will come later, the Joint Committee on Vaccination and Immunisation said.
The change in guidance means around 1.4 million teenagers will be eligible.
Prof Jonathan Van-Tam, England's deputy chief medical officer, said he expected the programme would start in "a very short number of weeks".
"There is no time to waste in getting on with this," he said. "I want us to proceed as fast as is practically possible."
The JCVI is a group of independent experts and their advice is a recommendation. It is then up to the governments of England, Scotland, Wales and Northern Ireland to put it into action.
Up until now, children over 12 are able to get a jab if they have certain health conditions, live with others who are at a high risk or are nearing their 18th birthday.
The only vaccine approved for those under-18 in the UK is Pfizer-BioNTech.
Some other countries have already been routinely vaccinating children over 12. The US has been doing so from May, as well as some European countries like France and Italy, after the EU gave them the go-ahead. Other countries that are vaccinating children include Brazil, Japan, Israel and Hong Kong.
Last month, the JCVI stopped short of opening up jabs to 16 and 17-year-olds as it wanted time to examine the risks and benefits, as well as reports of rare adverse effects such as inflammation of heart muscles.
The JCVI said earlier: "These are extremely rare and usually occur within a few days of the second dose, typically more in young men.
"Data from the USA suggests that, in males aged 12 to 17 years, 9.8 cases of myocarditis were reported per million first doses given. This rises to 67 per million after the second dose. Most people recovered quickly."
The JCVI said it expected one dose of the vaccine to give good protection against severe illness and hospitalisation in the 16 and 17 age group.
Prof Wei Shen Lim, who chairs the Covid part of the JCVI, said the change in advice wasn't just for the benefits to wider society. "Vaccination of children and young people can bring benefits to other people, such as adults and including parents and grandparents but, at the forefront, is the health and the benefits to children and young people themselves," he said.
Health Secretary Sajid Javid said he had asked the NHS in England to prepare to vaccinate those eligible "as soon as possible".
"The JCVI have not recommended vaccinating under-16s without underlying health conditions but will keep its position under review based on the latest data."
Covid: Jabs for 16 and 17-year-olds to start 'within weeks' - BBC News
