The first case of a new Covid variant of concern has been detected in Ireland.
According to Chief Medical Officer Dr Tony Holohan, two cases of BA.4, a subvariant of the Omicron strain, were detected earlier this month.
However, no cases of BA.5 have been identified.
The new variants BA.4 and BA.5 were designated as variants of concern by the European Centre for Disease Prevention and Control (ECDC) earlier this month.
The World Health Organisation’s infectious disease epidemiologist, Dr Maria Van Kerkhove, confirmed that the WHO had officially classified these as variants of concern, prompting fears of a new wave as cases spike in the coming weeks.
She said: “What we don’t have yet is information about the change of severity with these new sub lineages BA.4 and BA.5.”
The news comes less than two months after Prof Luke O’Neill warned that Omicron mutation BA.2 is 30% more infectious than Omicron and would “sweep up everyone who didn’t get Omicron”.
But epidemiologist Dr Van Kerkhove added that the new Omicron strains BA.4 and BA.5 are even more transmissible than BA.2, the dominant strain of Covid-19 in Ireland and globally.
She explained: “We know that BA.4 and BA.5 have growth advantages – it is more easily transmissible.
“This highlights the importance of surveillance and sequencing.”
Dr Van Kerkhove said there could be more Omicron mutations in the future “as the virus evolves” and said the force of potential new waves in countries like Ireland, which had large Omicron BA.2 waves, remained unknown.
She said: “We still need to monitor this virus very carefully because it still evolves. We don’t have certainty as to how it will evolve.”
The new strains were first discovered in South Africa at the beginning of this year and since have become dominant there.
BA.4 was first detected in South Africa and is now spreading in 20 heavily vaccinated countries worldwide, while BA.5 has been found in 19 countries.
The UK has also reported an increase in cases of the new variants with 115 cases of BA.4 and 80 cases of BA.5.
Dr Holohan said the two strains are more likely to spread as they can evade immunity provided by prior infection and vaccination as the immunity provided wanes over time.
In his May 13th report, he said that the overall epidemiological situation in Ireland remains positive but added: “we will need to continue to monitor developments with emerging variants over the coming weeks”.
“Although there continues to be high levels of infection and a significant number of cases receiving general hospital care, the numbers of detected infections and hospitalised cases have reduced considerably over recent weeks.”
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