Ireland is in the middle of another Covid wave as cases surge and hospitalisations continue to climb.
More than 23,000 cases were confirmed on Thursday, while over 1,400 people are being treated in hospital for the virus.
It comes as a more transmissible strain of the disease is now said to be "everywhere" here and almost impossible for people to avoid.
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Luke O'Neill, a professor of immunology at Trinity College Dublin, has said that the surge in cases is down to the BA.2 variant which is a "sister" of Omicron, albeit "much more infectious".
The 'stealth' variant is 30% more infectious than Omicron, which is already 70% more infectious than the previous strain of coronavirus.
He explained what makes this variant so transmissible and how it compares to other infectious diseases in terms of its ability to spread.
"It's all about spike protein, so the spike is the thing that sticks into your lungs and that gets into your body then and that's what's changing," he told the Irish Mirror.
"With these variants that have emerged, they all have slightly different spikes and the one in BA.2 is even stickier to your lungs.
"What that means is it can get in more easily on a lower dose, it latches on more, and that's why it's more transmissible."
The fact that it is 30% more transmissible than the already highly contagious Omicron BA.1 strain means it is likely the "most infectious" strain yet, he added.
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"That level of spread is very high for any virus, so other viruses that spread like wildfire would be measles, that's really infectious, and it's going in that direction," Prof O'Neill said.
"So it could turn out to be highly infectious, in terms of the league table of infectiousness, it's right up there.
"It's the most infectious SARS‑CoV‑2 we've seen, for definite."
While BA.2 is "everywhere", it's not clear as yet whether there are specific symptoms associated with it that differ from earlier strains, he added.
According to the ZOE Covid Study, dizziness and fatigue are among the commonly reported symptoms of BA.2, with other signs said to be a runny nose and a headache.
However, research is currently being conducted to ascertain if there are specific symptoms associated with BA.2 compared to earlier strains as it's too early to say yet, Prof O'Neill explained.
"The question now is if GPs see someone come in with BA2 will they notice a slight difference?" he said.
"Overall, it's similar, there's some evidence of more stomach problems or more gastrointestinal disturbances, but that hasn't been linked directly to BA.2 yet, that's just an assumption.
"What we do know is it grows more quickly, so the incubation time is shorter with it, so what that means is when it goes into your body, within two days you're getting a peak of virus in your body.
"Whereas with BA.1, with Omicron and the previous ones, that was about four days.
"So you see now people are picking it up and within two days, they're spreading it and getting symptoms more quickly and that creates problems for obvious reasons because it spreads more readily as a result of that.
"We may see different symptoms then because it's growing much faster in people."
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