Children who are at increased risk of Covid-19 are to be offered the Pfizer/BioNTech vaccine on the NHS “as soon as possible”, as are those living with people with weakened immune systems, the Health Secretary has announced.

Sajid Javid said he had accepted the advice of the independent Joint Committee on Vaccination and Immunisation (JCVI), which has ruled out mass vaccination of healthy children for now.

The move means thousands of children in the UK aged 12 to 15 with the following conditions can access the vaccine: severe neuro-disabilities, Down’s syndrome, immunosuppression, multiple or severe learning disabilities.

Other conditions, including type 1 diabetes, are not currently included in the list.

Under existing guidance, young people aged 16 to 17 with underlying health conditions which put them at higher risk of serious Covid should have already been offered a jab.

The JCVI has also said those aged 12 to 17 who live with an immunosuppressed person, such as a parent or grandparent, should be offered a Covid vaccine.

This is to protect loved ones at home who are at higher risk of serious coronavirus and who may not get the full immune protection from their own Covid vaccines.

Mr Javid said: “Today’s advice does not recommend vaccinating under-18s without underlying health conditions at this point in time.

“But the JCVI will continue to review new data, and consider whether to recommend vaccinating under-18s without underlying health conditions at a future date.

“Covid-19 vaccines have saved almost 37,000 lives and prevented around 11.7 million infections in England alone.

“They are building a wall of defence and are the best way to protect people from serious illness. I encourage everybody who is eligible to get their jabs as soon as they can.”

Announcing the move in the Commons, vaccines minister Nadhim Zahawi, said: “I know that people will have questions about what it means for them and their children, but I can assure them that nobody needs to come forward at this stage. The NHS will get in touch with them at the right time and they will make sure that the jabs are delivered in a setting that meets their complex needs.”

He earlier apologised to the Speaker for having made reference to the announcement on TV before telling MPs.

The JCVI said it was not currently advising that children outside these groups receive a vaccine because the benefits do not outweigh the potential risks.

Fewer than 30 children have died of Covid-19 in the UK as of March, and Covid rarely causes severe disease in children without underlying health conditions.

Real-world data on the safety of Covid-19 jabs in children is currently limited, but there have been rare reports of myocarditis (inflammation of the heart muscle) and pericarditis (inflammation of the membrane around the heart) following the use of the Pfizer/BioNTech and Moderna vaccines in millions of younger adults.

The incidence of these issues is put at around one in 20,000 people, though this is a broad estimate.

The JCVI said that until more safety data is provided and evaluated, it is adopting a precautionary approach.

The Pfizer/BioNTech vaccine is the only vaccine that has been authorised for children in the UK aged 12 or older.

A US clinical trial in about 1,000 children aged 12 to 15 found that if youngsters suffered any side-effects from the jab, they were only short-lived and mild.

Professor Adam Finn, a professor of paediatrics at the University of Bristol, told a briefing it was an “evidence-based decision” which will be “constantly” kept under review.

He added the decision for the recommendation came after Pfizer announced the results of its study into its vaccine on children last month.

The results of the study led the JCVI to also analyse real-world data from the UK and other countries surrounding vaccines and the effect of the disease on children.

He said: “The virus very rarely affects children seriously, particularly children who are healthy. The deaths and serious cases that we’ve seen in children have, for the most part, been in children with a number of underlying conditions which seem to predispose them to serious disease.

“In fact, those children are a much narrower group than the ones that we originally conceived might be at risk and designated clinically extremely vulnerable. It’s critical that informed consent is obtained in a careful way both from the parents and the child themselves.”

He added pregnant teenagers under the age of 16 would not be included in the list of recommendations as “the risks of serious disease in teenagers gets progressively lower as they get younger” however this guidance is “being kept under close review.”

Alongside the at-risk groups, young people who are within three months of their 18th birthday will also be invited for a jab, meaning around 370,000 overall will be eligible.

Experts hope this will ensure good uptake of the vaccine in newly-turned 18-year-olds.

Professor Anthony Harnden, deputy chairman of the JCVI, said: “The primary aim of the vaccination programme has always been to prevent hospitalisations and deaths.

“Based on the fact that previously well children, if they do get Covid-19, are likely to have a very mild form of the disease, the health benefits of vaccinating them are small.

“The benefits of reducing transmission to the wider population from children are also highly uncertain, especially as vaccine uptake is very high in older people who are at highest risk from serious Covid-19 infection.

“We will keep this advice under review as more safety and effectiveness information becomes available.”

Regarding long Covid, experts say it is not currently clear that vaccination prevents such illness and therefore a mass vaccination programme could not be implemented with the hope of preventing it.

Gemma Peters, chief executive of Blood Cancer UK, welcomed the move by the JCVI, as did Richard Kramer, chief executive of the disability charity Sense.

He said: “Many of the disabled children we support have underlying health conditions and they and their families have been shielding for over a year now, forgotten during the pandemic and as part of the UK vaccination programme.

“This news will come as a huge relief and reassurance especially with most restrictions now lifted and cases rising.”

But shadow health secretary Jonathan Ashworth questioned why the UK was not vaccinating healthy children, saying they could become sick with long Covid.

He also asked Mr Zahawi in the Commons to “guarantee this decision was made on medical grounds not on grounds of vaccine supply”.

Elsewhere, scientists gave a mixed reaction, with Dr Stephen Griffin, from the University of Leeds, saying he was “extremely disappointed” in the decision and the JCVI seemed “untroubled” by infections among the under-18s and long Covid.

But Professor Paul Hunter, from the University of East Anglia, said it was not clear how many children had already had the infection and recovered.

He added: “The decision about giving vaccine to children should not be made on whether or not it protects others in society.”