More than a third of all adults in England have now received an extra dose of Covid-19 vaccine.
A total of 15,233,461 booster and third doses had been given to people aged 18 and over as of November 29, NHS England figures show.
This is the equivalent of 34.3% of all people in this age group, based on the latest population estimates.
It is up from 29.4% a week earlier and 15.8% at the start of November, according to analysis by the PA news agency.
England is the second UK nation to pass this milestone, with Scotland reaching it last week.
The figure for Scotland now stands at 38.0%.
The UK Joint Committee on Vaccination and Immunisation (JCVI) recommended on Monday that all adults aged 18 to 39 should be offered a booster dose of the Covid-19 vaccine, in order of descending age groups, to increase their level of protection against the recently detected Omicron variant.
Those aged 40 and over are already eligible for a booster vaccine.
The JCVI also advised that the timing of the booster should be cut from six months after a second dose to three.
Other groups currently able to receive a booster include frontline health and social care workers, along with adults aged 16 and over with underlying health conditions that put them at higher risk of severe coronavirus.
Third doses – the other type of extra dose – are available eight weeks after a second dose to people aged 12 and over with severely weakened immune systems.
In Northern Ireland, 389,707 booster and third doses have now been given to people aged 18 and over, according to the Northern Ireland Department of Health.
This is the equivalent of 26.8% of the entire adult population.
Wales does not publish a full breakdown by age group of the take-up of extra doses, instead giving the figures only for booster doses.
These show that 835,689 boosters had been given to those over 18 as of November 29, according to Public Health Wales – the equivalent of 32.9% of the age group.
Percentages are based on the latest official population estimates for the UK, which are for mid-2020 and are used by the Government and the UK health agencies for reporting levels of vaccine take-up.
Overall, 18,215,535 booster and third doses of vaccine have now been delivered across the UK – the equivalent of 27.2% of the whole population.