More than 85% of adults in England, Wales and Northern Ireland have some protection against Covid-19, new data suggests.
Scotland has the lowest levels of coronavirus protection with 79.1% of adults estimated to have antibodies in their bloodstream.
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 figures, from the week beginning June 7, are up from the last data revealed by the Office for National Statistics (ONS), which found that around eight in 10 adults across most of the UK had Covid antibodies.
In England, an estimated 86.6% of the adult population "in the community" would have tested positive for antibodies in the week beginning June 7, according to the statistics agency.
The "community" refers to private homes, and excludes those in hospitals, care homes or other institutional settings.
In Wales, it is estimated 88.7% of the adult population has antibodies.
In Scotland, the estimate is 79.1%, and in Northern Ireland, the figure is 85.4%.
The ONS estimates that between 81.8% and 86.2% of adults in the UK received at least one dose of a Covid vaccine at the time the survey was undertaken. And it estimates that between 49.6% and 66.8% were fully vaccinated in the week beginning June 7.
It added more than 95% of adults aged 50 years and older have received at least one vaccine dose and more than 95% of those aged 70 and order have been fully vaccinated.
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Sarah Crofts, head of analytical outputs for the ONS' Covid-19 Infection survey said: “Across the UK, at least 80% of adults now have some level of antibody protection against COVID-19.
“With infection levels now increasing again in England, this protection will hopefully protect the majority against severe symptoms.
“With vaccinations now open to the under 30s we must continue to monitor how antibody levels change over the coming months.”