LONDON: Britain will administer coronavirus vaccines to clinically vulnerable youngsters, the government said Monday, but not to all children due to an ongoing review into potential side effects.

Young people aged 12 to 15 with severe neuro-disabilities, Down's Syndrome, immunosuppression and multiple or severe learning disabilities will be eligible for vaccination, vaccines minister Nadhim Zahawi said.

He told parliament the move follows advice from the independent Joint Committee on Vaccination and Immunisation (JCVI).

Health Secretary Sajid Javid said he had accepted the recommendations "and I have asked the NHS (National Health Service) to prepare to vaccinate those eligible as soon as possible".

Britain's medicines regulator has already approved the Pfizer/BioNTech vaccine for youngsters aged 12 and over, noted Javid -- who is currently self-isolating after contracting Covid.

"Today's advice does not recommend vaccinating under-18s without underlying health conditions at this point in time," he said in a statement.

"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," he added.

Anyone about to turn 18 within the next three months will also be offered a shot.

Britain has fully innoculated almost 70 percent of its adult population, but is in the midst of another wave of the virus due to the emergence of the Delta variant, first identified in India.

Cases are hitting levels not seen since winter, although deaths and hospitalisations remain relatively low, and the government on Monday largely reopened England's economy.

Zahawi warned "these numbers will get worse before they get better". The vaccine rollout has slowed in recent weeks, with younger people more reluctant to get jabbed.

Zahawi told Sky News that there have been cases of inflammation of the heart in some vaccinated children and that the JCVI will continue to review that data before opening up the programme further.

"On balance, I think the JCVI are coming down on the side of continuing to review all children, healthy children, but wanting to protect the vulnerable children first," he said.

He added that the country's vaccine programme "has given us extra legs in our race against the virus", and that plans were being drawn up for a potential round of booster shots before the winter.