The University of Oxford plans to test its Covid-19 vaccine on children as young as six.
Organisers of the trial, which was announced on Saturday, seeks to recruit 300 volunteers aged between six and 17.
It is the latest vaccine developer to assess whether its Covid-19 inoculation is effective in young people.
Andrew Pollard, chief researcher on the Oxford vaccine trial, said that while most children with Covid-19 do not become severely ill, “it is important to establish the safety and immune response to the vaccine in children and young people as some children may benefit from vaccination”.
The study will take place at three English cities, London, Southampton and Bristol, and assess its safety and the immune responses in children.
Investigators will test the shot on youngsters aged 12 to 17 first before moving to the younger age group, with initial data expected by summer.
The study will look at two dosing stages one month and three months apart, Mr Pollard said.
“We planned to conduct child trials from the beginning to make sure that we had the greatest opportunity for access across all ages to the vaccine,” Mr Pollard said.
“I’m absolutely delighted that today we’re launching the paediatric trials after this long road that we’ve been on.”
Regulators in more than 50 countries have authorised widespread use of the Oxford vaccine, which is being produced and distributed by AstraZeneca, for use in people over the age of 18.
Other drug companies are also testing the Covid-19 vaccines in children.
In October, Pfizer-BioNTech’s vaccine which has already been authorised for use in people aged 16 and older, was tested on children as young as 12.
Two months later, Moderna began testing its vaccine on children aged 12 and up.
Mr Pollard said the Oxford trial should help policymakers decide whether at some point in the future they want to extend mass inoculation programmes to children, to improve safety in schools and combat the spread of the virus in the wider population.
“For most children, for themselves, Covid-19 is really not a big problem,” he said.
“However, it is certainly possible that wider use to try and curb the progress of the pandemic might be considered in the future, so here we’re just trying to establish the data that would support that if, indeed, policymakers wanted to go in that direction.”
The two-dose Oxford-AstraZeneca shot was hailed as a “vaccine for the world” because it is cheaper and easier to distribute than some rivals.
AstraZeneca has a target of producing three billion doses this year and aims to produce more than 200 million doses per month by April.
The ruling came after some European countries, including France, Germany and Denmark, approved the vaccine for use only in the under-65 age group, with those nations citing a lack of data on safety for older people.
On Saturday, UK ministers urged people in the top four priority groups to be vaccinated in a bid to meet its target of 15 million people having the first dose by Monday.
It came as Health Secretary Matt Hancock said the UK could live with Covid-19 “like we do with flu”.
"I hope that Covid-19 will become a treatable disease by the end of the year," he told the Daily Telegraph.