Almost 90 per cent of blood donors aged in their 20s show signs of having been infected with Covid-19, figures from the State’s infectious disease monitoring body show.
The Health Protection Surveillance Centre (HPSC) monitored the disease’s seroprevalence, the proportion of people with antibodies in their blood showing they have been exposed to the virus, between last October and the end of June.
It found that seroprevalence, which would include vaccination as well as infection, was at 99 per cent among blood donors.
The HPSC said seroprevalence indicating someone had been infected with Covid-19 was “relatively high”, with 69 per cent of donors having had the disease at some point.
The proportions showing evidence of an infection varies by age group, with the highest levels (87 per cent) recorded among those aged 20-29. The rate for the 30-49 age group was 71 per cent and this fell to 60 per cent among people aged 50-79.
[ Autumn Covid vaccine rollout: Third booster for pensioners and immunosuppressedOpens in new window ]
Almost 1.64 million Covid-19 cases have been detected by PCR tests in Ireland since the pandemic began.
Meanwhile, Dr Cillian De Gascun, director of the National Virus Reference Laboratory, said no cases of BA.2.75, the new Omicron subvariant also known as Centaurus, have been detected in Ireland yet. First detected in India, the subvariant has since been identified in countries including Germany, the UK and the US.
World Health Organisation chief scientist Soumya Swaminathan said the new variant appeared to have mutated in a way that could indicate “major immune escape” and that it had a “clear growth advantage” over other variants in India.
Dr De Gascun said 97 per cent of Covid-19 cases sequenced by the laboratory had the “S gene target failure” marker identifying them as Omicron variants BA.1, BA.3, BA.4 or BA.5, while the remainder are likely to be the BA.2 Omicron variant or derivatives of that.
He said emerging data suggest BA.2.75 will not be as immune evasive as BA.5, but said more information on this was expected in the coming weeks.
Latest figures indicate the State is past the peak of the recent wave of infection, with 631 people in hospital with the virus on Sunday morning, significantly down on 1,055 patients two weeks ago.
The surge, which was attributed to the highly-transmissible BA.4 and BA.5 Omicron sublineages, is showing early signs of slowing or potentially stabilising, the most recent update from interim chief medical officer Prof Breda Smyth, dated July 15th, states.
Separately, Minister for Health Stephen Donnelly on Saturday announced the next phase of Ireland’s Covid-19 booster vaccination programme.
Children aged five to 11 who are immunocompromised will be eligible to receive their first booster vaccine, while a second will be rolled out for those aged 12-49 who have an underlying medical condition or are living in long-term care facilities.
Individuals aged 50-64 are now to be eligible for a second booster, as are healthcare workers and pregnant women at 16 weeks or later who have not already received a booster during their pregnancy.
A third booster for those aged 65 years and older, and for those aged 12-64 who are immunocompromised is also recommended.
