The uptake of Covid booster jabs may be too slow to prevent hospitals from becoming overcrowded this winter, experts fear.
One month into the programme, only half of eligible over-80s have received a third dose, despite being at heightened risk, NHS figures suggest.
Of the 2.2 million who had a second jab more than six months ago, fewer than 1.2 million have had the booster.
The number of people aged 65 to 84 admitted to hospital has risen 19 per cent in the past week, with admissions up 8 per cent among people over 85.
Yesterday the UK reported 45,140 cases of coronavirus and 57 deaths within 28 days of a positive test.
One month into the programme, only half of eligible over-80s have received a third dose, despite being at heightened risk, NHS figures suggest
Boosters have become a key part of the Government's winter plan, along with the vaccination of children aged 12 to 15.
Data from the Zoe Covid study shows the effectiveness of the AstraZeneca vaccine at stopping severe illness falls from 74 per to 67 per cent after six months.
Azeem Majeed, professor of primary care at Imperial College London, said it was inevitable people would lose some enthusiasm for the jabs, telling the Sunday Times: 'There was always going to be a drop-off between doses. It's likely that some people who got a second dose won't get a third. They're just not interested.
Azeem Majeed, (pictured), professor of primary care at Imperial College London, said it was inevitable people would lose some enthusiasm for the jabs, telling the Sunday Times: 'There was always going to be a drop-off between doses. It's likely that some people who got a second dose won't get a third. They're just not interested'
Yesterday the UK reported 45,140 cases of coronavirus, bringing the total number of infections to 8,449.165
The number of Covid deaths in the UK yesterday was 57, down 61 per cent on last Sunday
'People were initially told that two doses were enough. They were in lockdown, and the vaccine was their ticket out of it. Now there's much less incentive.'
Duncan Robertson, of Warwick University, said delays in administering the jabs will have to be 'resolved immediately' to avoid unnecessary pressures on the NHS.
'Booster vaccinations are there to prevent hospitalisations and ultimately to save lives,' he said. 'Delays matter.' In England, about 25 million people over 50 and vulnerable adults will be eligible for boosters by the end of winter.
However, at the present rate of 175,000 a day, some in their early 50s may not have boosters until mid-February – about eight months after most were double-jabbed.
Those eligible are urged to book an appointment online or by phoning 119.
What is a 'booster' jab?
The 'booster' is a third dose of the coronavirus vaccine, and gives greater and longer-lasting protection than the initial two doses.
A study by Public Health England found immunity starts to wane around 20 weeks after receiving the second dose, particularly in the elderly. This means people gradually become more likely to catch the virus, end up in hospital or die.
The CovBoost trial, which explored the impact of giving a third dose, found a booster jab increases antibody levels and cellular responses beyond that achieved with two.
Who will get one?
Around 32 million people in the UK will initially be offered a booster vaccine.
They will be offered to everyone in priority groups one to nine during the initial vaccine rollout.
These include those aged 50 and over, those living and working in elderly care homes, and frontline health and social care workers. All those who are clinically extremely vulnerable and anyone aged 16 to 65 in an at-risk group for Covid are also eligible.
When will I get my jab?
The Joint Committee on Vaccination and Immunisation (JCVI) recommends you wait until at least six months after your second dose.
Health officials hope to have offered a booster jab to all those eligible before Christmas, to ensure as many as possible have high levels of protection in the depths of winter.
Which booster vaccine will I get?
The JCVI has recommended the Pfizer vaccine as its preferred option, regardless of what you received for doses one and two.
A half dose of Moderna may also be used as a booster but the AstraZeneca/Oxford vaccine will be used only if patients are allergic to the others.
Will I still get a flu jab?
The NHS is embarking on its biggest-ever flu vaccination programme and wants those who are eligible to take up the offer of both jabs.
The MHRA has approved the use of the Covid and flu vaccines at the same time.