Children aged 12 to 15 will be offered a COVID vaccine, the UK's chief medical officers (CMOs) have decided.
England's Professor Chris Whitty said they came to their decision after considering "what effect this will have on transmission in schools and effects on education".
"It's a useful tool to reduce the disruption," he added.
They will be offered a single dose of the Pfizer vaccine and the rollout should begin "as soon as possible", England's deputy CMO Jonathan Van-Tam said.
The move means around three million children could be eligible for the jab, which is expected to be given through schools.
In their advice to the government, the CMOs said they were recommending vaccines on "public health grounds" and it was "likely vaccination will help reduce transmission of COVID-19 in schools".
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They added: "COVID-19 is a disease which can be very effectively transmitted by mass spreading events, especially with Delta variant.
"Having a significant proportion of pupils vaccinated is likely to reduce the probability of such events which are likely to cause local outbreaks in, or associated with, schools.
"They will also reduce the chance an individual child gets COVID-19. This means vaccination is likely to reduce (but not eliminate) education disruption."
It comes following a review by the four CMOs of the decision by the Joint Committee on Vaccination and Immunisation (JCVI) not to advise the move.
Children recently returned to school, and there are concerns of a rise in cases following the summer holidays.
The JCVI advised the government to look at "wider issues" – including the impact on schooling – when making the final decision.
The independent regulator, the Medicines and Healthcare products Regulatory Agency (MHRA), approved the Pfizer and Moderna vaccines for those aged 12 and over after ruling they met strict standards of safety and effectiveness.
In its advisory report, the JCVI said the "individual" health benefits from vaccination for children aged 12 to 15 was small.
The risk of potentially serious side effects – including myocarditis – is "very rare, but potentially serious".
The Department of Health and Social care previously said that, like other school vaccination programmes, parent or carer consent will be sought.
Health Secretary Sajid Javid told Sky News that a child's decision "will prevail" in the case of a conflict.