The new 'Eris' coronavirus strain is on the rise in Ireland, according to Professor Luke O'Neill.
The new strain is becoming more prominent in several countries.
Trinity College immunologist has said while Ireland has seen a large increase, it's coming from a low base.
The new Omicron variant EG.5 - or Eris - has been designated a variant of interest by the World Health Organisation.
Prof O'Neill told The Pat Kenny Show the numbers are going up.
"In Ireland there was a 51.8% increase between week 30 and week 29 in cases," he said.
"That seems like an awful lot, but it's a low base - they've gone right down in June.
"Very low numbers in June, but now it's going up".
In a risk evaluation published on Wednesday, the WHO said there has been a "steady increase in the proportion of EG.5 reported."
The global prevalence was 17.4% in the past week, which the WHO said is a "notable rise" from data reported four weeks prior, when the prevalence of EG.5 was just 7.6%.
A total of 7,354 sequences of Omicron EG.5 have been submitted from 51 countries as of August 7th.
The largest portion of that is from China at 30.6%. This was followed by:
- The USA (18.4%)
- Korea (14.1%)
- Japan (11.1%)
- Canada (5.3%)
Similar numbers were also found in Australia, Singapore, the UK, France, Portugal and Spain.
Prof O'Neill said symptoms can include the "same old" runny nose, sore throat, muscle aches, "but interestingly, less shortness of breath”.
"Loss of smell is less of a feature as well, and less fever,” he said.
"This one [is] less severe in terms of overall symptomology.
"It's probably because our immunity is so strong. Every time a new variant crops up now, the hope is you've built up immunity anyway to the previous ones.
"You fight it more effectively and hence there's less symptoms".
'Nothing to worry about'
Prof O'Neill said the variant is growing quickly.
"It's growing [to] a 20% increase per week in the UK, for instance," he said. "In the US at the moment 17.3% of cases are Eris".
"The previous variant - Kraken, XBB1 - that now seems to be going down [and] Eris is going up".
Prof O'Neill said the new strain is not a variant of concern.
"Nothing to worry about here, yet, thankfully," he said.
"[There is] no increase in disease, shall we say, it just seems to be more transmissible.
"So, there's more people catching it, but as ever, you've got to keep an eye on it.
"If it spreads more and more, the risk of more variants is always there every time the virus divides.
"At the moment, no massive, increase in hospitalisations - [there is a] slight increase, upticks here and there.
"Nothing to worry about yet, is the view," he added.
The United Nations has said the number of reported cases, hospitalisations and deaths reported globally has continued to decline since an end was declared to the global health emergency three months ago.
The HSE's COVID Tracker App has also been stood down since the beginning of this month.