Nearly nine in 10 people in the UK aged 16 to 24 have Covid antibodies, according to official estimates.
The Office for National Statistics, which carried out blood tests on youngsters across the UK’s four nations, found between 87 and 89 per cent of them had antibodies that help fight the virus.
The presence of coronavirus antibodies suggests someone has been infected in the past or has been vaccinated.
However, they are not a perfect measure of whether a person is protected against Covid, as other parts of the immune response are involved in fighting the virus, such a T-cells.
The steady increase seen across the UK has coincided with the rollout of Covid vaccine to younger age groups.
First doses of vaccine have been available to teenagers aged 16 and 17 for several weeks, while all over-18s have been eligible for a jab since June.
And with the first over-12s being given the vaccine from September 22, a similar surge in antibodies could be seen among this age group.
But levels are falling among older age groups, who were the first to get the jab when the rollout began last December.
Ministers hope its booster programme for over-50s, vulnerable Britons and frontline health workers, will keep immunity high heading into winter.
But if the NHS falls under huge pressure from an expected surge in cases, hospitalisations and deaths, ministers have planned to bring back face masks and working from home.
And they have cautioned that, while a lockdown is the last resort, it has not be ruled out.
An average of 88.7 per cent of people aged 16 to 24 had Covid antibodies, according to ONS estimated based on blood tests taken on the week of August 23
It takes two to three weeks for antibodies to develop after either catching the virus or getting vaccinated.
They then remain in the blood – helping to stop someone getting the same infection again and suppress severe symptoms if they do – but drop over time.
Research so far has found protection begins waning six months after vaccination, leading officials to announce this week that vulnerable people will be offered booster vaccines from this point.
In England and Scotland, 88.7 per cent of those aged 16 to 24 had Covid antibodies, while the figure stood at 86.9 per cent in Wales and 87.2 per cent in Northern Ireland, according to the ONS estimates.
Antibody positivity among 16 to 24-year-olds is ‘increasing steadily across all four UK countries’, the ONS said.
Life expectancy falls to lowest level in a DECADE due to Covid pandemic
Life expectancy in England reached its lowest level in a decade because of the Covid pandemic, official figures have revealed.
Public Health England (PHE) claimed the ‘very high level’ of excess deaths in 2020 caused by the pandemic saw life expectancy in men to drop by 1.3 years to 78.7. For women, the rate dropped 0.9 years to 82.7.
This is the lowest since 2011 for both genders, according to the Government agency’s Health Profile for England report.
And the gap in how long people live based on deprivation reached the highest ever recorded, which it said demonstrated that the pandemic ‘exacerbated existing inequalities’.
Men living in the least deprived areas can expect to live a decade longer than those in the run-down boroughs, while the difference for women is 8.5 years.
And there was differences across the country, with London seeing the biggest fall in life expectancy. The South West and East of England saw the smallest drops.
Since the virus hit the UK last year, almost 120,000 people in England have died within 28 days of testing positive for the Covid.
In England the percentage of 16 to 24-year-olds likely to have Covid-19 antibodies has jumped from 60.6 per cent in the week beginning June 21 to 88.7 per cent in the week beginning August 23.
In Wales the figure has risen from 63.4 to 86.9 per cent in the same period.
In Northern Ireland it has increased from 58.7 to 87.2 per cent.
Scotland has seen a particularly sharp rise, from 51.1 to 88.7 per cent.
Antibody levels have levelled off or declined slightly among adults in old age groups, however.
The ONS said: ‘In more recent weeks our estimates suggest those aged 25 to 64 years have similar or slightly higher antibody levels than those aged 65 years and over.
‘This is line with vaccinations for many of those in younger age groups occurring more recently.’
Many people in the oldest age groups, such as 75 to 79 or 80 and over, are likely to have received both doses of vaccine earlier this year, possibly more than six months ago.
Levels of antibody positivity are defined by a fixed amount of antibodies in the blood.
‘Most older people who are vaccinated will retain higher antibody levels than prior to vaccination but may have a lower number of antibodies in the blood at the time of testing,’ the ONS added.
In England an estimated 91.5 per cent of people aged 80 and over were likely to have Covid-19 antibodies in the week beginning August 23, down from 93.7 per cent two months earlier.
In Wales the proportion has dropped from 91.5 to 82.0 per cent, while in Scotland it is down from 88 to 85.9 per cent.
For Northern Ireland, the estimate for those aged 70 and over has fallen from 93.4 to 87.4 per cent.
The ONS said there a clear pattern between vaccination and testing positive for Covid antibodies, but ‘the detection of antibodies alone is not a precise measure of the immunity protection given by vaccination’.
Overall an estimated 93.6 per cent of the adult population of England was likely to have tested positive for Covid antibodies in the most recent week, while the figure was similar in the other three nations.