A fourth Covid vaccine dose looks set to be rolled out to millions more Brits this autumn, Sajid Javid has declared.
The Health Secretary said he expects "a lot more" people to get their second booster jab before Christmas.
It's already the case that all 7.2million over-75s, care home residents, and 500,000 immunosuppressed adults or teenagers can get a fresh dose this Spring.
For most of them it will be the fourth dose, though for immunosuppressed people it might be the fifth.
However, these fourth doses - due "around 6 months" after a person's third dose - have not yet started in England, despite having done so in Scotland and despite a rise in cases.
The Mirror's Health Editor Martin Bagot reports that these fourth doses to over-75s, vulnerable people and care residents could start next week.
An NHS England spokesman said: “The NHS will be vaccinating eligible people with a spring dose six months after their first booster, starting later this month for the small number of people eligible before April.”
Meanwhile, the Joint Committee on Vaccination and Immunisation (JCVI) is still debating whether to extend fourth doses more widely.
Last week Sajid Javid said the idea of a wider rollout of fourth doses was being "kept under review" amid rising cases in the UK.
Last night, the Health Secretary gave the strongest hint yet that there will definitely be a wider rollout.
But is understood no decisions have been made about whether to offer a fourth jab to all adults - or, instead, widen access but still keep it to certain groups such as the over-50s.
Asked if the JCVI would say we needed more people jabbed, Mr Javid told ITV's Peston: "I think at some point they will.
"And they've actually been clear and their most recent advice is that they think that towards the end of this year, maybe in the autumn, there will be a need to give a lot more people a boost, an offer of a boost.
"But I'll wait for that advice."
The JCVI has explicitly said that even if there is a widespread fourth dose rollout, it could be limited to some groups.
The experts said last month: "A further booster in the autumn of 2022 is likely to be advised for people who are at higher risk of severe COVID-19.
"It remains too early to set out precise details of what that programme may look like, but the committee will provide more definitive advice in due course."
Mr Javid said: "When it comes to vaccinations I think we rightly take the advice of our clinicians. There's a committee, it's called the JCVI and we listen very carefully to what they've got to say.
"They look at the data very, very carefully and their latest advice as you say is that there should be a second boost - or let's call it a fourth dose, but to focus on those over 75, those in care homes, those who are immunosuppressed.
"Now we will start that by the end of this month, that's what we've said and we're completely on track for that."
JCVI chief Prof Wei Shen Lim has previously suggested the sped-up booster rollout - with three months instead of six between second and third doses, due to Omicron - could mean the interval before a fourth dose has to be shortened too.
He said in December that waiting three months, not six, for a booster dose “might mean a lower peak protection”.
He told MPs: “If you get the booster at six months and you teach a higher level, say 200, and that wanes at a certain constant rate, to drop from 200 to 50 would take a period of time.
“If you get the booster at three months and the peak level it can get to is lower, say 150, and it wanes at the same rate, it will reach 50 at an earlier time point.”
Meanwhile, Ukrainian refugees who come to Britain will be given a Covid vaccine.
Thousands of refugees are due to start arriving next week, and will be offered a jab as the vaccination rate is a third of the population.
Mr Javid said: "They will have access to their local GPs, just like you and I, they will have access to local schools.
“I think it's really important that we give people from Ukraine, our friends, the warmest, most generous possible welcome.”
