Around eight in 10 adults in most parts of the UK now have some protection against Covid-19, latest data suggests.
Figures from the Office for National Statistics (ONS) estimate that 82.7% of Welsh adults, 80.3% of English adults and 79.9% of over-18s in Northern Ireland have coronavirus antibodies which allow them to fight off infection from the respiratory disease.
In Scotland the estimate is slightly lower, at just over seven in 10 adults or 72.6%.
The presence of Covid antibodies in someone's blood suggests they have had the infection in the past or received at least one dose of a vaccine.
It takes between two and three weeks after infection or vaccination for the body to make enough antibodies to fight the virus.
Antibodies then remain in the blood at low levels, although these levels can decline over time to the point that tests can no longer detect them.
The latest estimates are from the ONS and are based on a sample of blood test results for the week beginning May 17, meaning the percentage of adults with Covid antibodies is likely to be higher than the latest figures available.
The estimates are for people in private households and do not include settings such as hospitals and care homes.
In both England and Northern Ireland, the latest estimate of eight in 10 adults is up from around seven in 10 a month ago, while in Wales the estimate of eight in 10 is up from around two-thirds of adults.
For Scotland the estimate is up month-on-month from around six in 10 to just over seven in 10.
The ONS said there is a clear pattern between vaccination and testing positive for Covid-19 antibodies but the detection of antibodies alone is not a precise measure of the immunity protection given by vaccination.
Once infected or vaccinated, the length of time antibodies remain at detectable levels in the blood is not fully known.
It is also not yet known how having detectable antibodies, now or at some time in the past, affects the chance of getting Covid-19 again.
In England, the highest percentage of adults testing positive for Covid-19 antibodies in the week beginning May 17 was estimated to be the 70 to 74 age group (97.8%), followed by people aged 75 to 79 (97.2%) and 80 and over (95.8%).
The lowest percentage was for 16 to 24-year-olds (52.8%).
In Wales, the highest proportion of adults likely to have tested positive for antibodies was also the 70 to 74 age group (98.5%) followed by 75 to 79 (98.0%), while in Scotland the highest percentage was for people aged 70 to 74 (97.0%) followed by 65 to 69-year-olds (95.8%).
In Northern Ireland, the ONS uses different age groups due to small sample sizes and estimates 94.0% of people aged 70 and over were likely to have tested positive for antibodies in the week beginning May 17.
Latest figures show that as of the end of Monday, June 7, 40,573,517 or 77% of UK adults have had at least one dose of the Covid vaccine, while 28,227,362 or 53.6% have had both jabs.
Despite people having high levels of Covid antibodies and the majority of UK adults being vaccinated, coronavirus levels are rising, due to the easing of lockdown restrictions in recent weeks and the Delta variant (formerly known as the Indian variant) being more transmissible.
As of 9am on Tuesday, a further 6,048 people tested positive for coronavirus, a rise of 60.6% in the last week.
These increasing rates of the virus mean that the ending of all restrictions in England on June 21 is looking less and less likely.
On Wednesday, a Whitehall source suggested Chancellor Rishi Sunak may be willing to accept a short delay to Step 4 of the road map to ending the lockdown.
The source pointed towards the Treasury having gone “long” on emergency coronavirus support packages in the Budget to cover the possibility of a delay to the plans.
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