One in seven adults has Covid antibodies as vaccine effects emerge in Wales, ONS suggests
The number of people who have antibodies for the virus that causes Covid-19 has increased in Wales, highlighting the impact of the vaccination rollout.
The Office for National Statistics (ONS) has estimated that one in seven adults in Wales would have tested positive for antibodies against the virus on a blood test in the 28 days up to 1 February.
The ONS said more than 14% of the Welsh population would have tested positive for antibodies from a blood sample during that period.
Having antibodies in the blood indicates that people have either previously been infected with the virus or have had a Covid-19 vaccine.
Last week, Wales reached its first major milestone in the vaccination rollout by offering everyone in the first four priority groups a jab.
Figures showed that those in Wales aged between 16 and 24 were more likely to test positive for antibodies.
In England, an estimated one in five adults would have tested positive for antibodies during that period, with older people more likely to have them.
This compares to one in seven Northern Ireland and an estimated one in nine in Scotland.
Antibodies can take around two weeks after vaccination to emerge, meaning those vaccinated first will be among the first to show antibodies through blood tests.
The ONS has suggested that the increasing number of people with antibodies reflects high levels of infection, as well as the effect of the vaccine rollout.
It comes after the Welsh Government announced a planned reduction in the number of vaccines being administered, but the First Minister insisted this would not delay the rollout.
Latest Public Health Wales figures show that 163,866 people aged 80 and over in Wales have received their first dose of the vaccine.
According to the ONS figures, 40.9% of people aged 80 years and over testing positive for antibodies in England. In Scotland that figure was 11.6%.
The data for Northern Ireland includes those over the age of 70 and 9.1% of this group are estimated to have antibodies for the virus.
But experts said that it is still not known how long antibodies last for.
Esther Sutherland, principal statistician for the Covid-19 Infection Survey, said: "Antibody positivity rates have increased across all four nations and the effects of the vaccination programmes have begun to appear, especially in the older age groups.
"We would expect younger groups to have high levels of antibody positivity after the period of high infection rates we have seen in the last few months.
"We will continue to closely monitor antibodies as the UK vaccination programmes continue to be rolled out."