Concerns have been raised over a subvariant of Covid that is set to become dominant in Ireland by the end of the month.
Initial studies have indicated that BA.2, a subvariant of Omicron, is more transmissible and could cause more severe illness than previous strains.
Trinity Immunology Professor Kindtson Mills said BA.2 is one and a half times more infectious than Omicron and has already become dominant in Denmark and the Netherlands.
Speaking to RTE's Claire Byrne, he said: "The fact that it's pushing out the other version of Omicron suggests that it's either evading immunity better or it's more transmissible, and all the evidence suggests that it's more transmissible."
However, Prof Mills said there was no need to panic as the "severity is still unknown" due to contradictory data from various worldwide studies.
He said Japanese scientists found that BA.2 "might be more dangerous", but all the data from Denmark and Ireland has suggested that there will be no change in hospitalisations compared with Omicron.
"That's very good news. If that is the case, well it can be treated in the same way as Omicron in terms of not resulting in a huge number of hospitalisations or ICU admissions," explained Prof Mills.
He said there is a "selective advantage" for a virus that transmits more readily but does not kill its host, and "that's the case with Omicron and with the subvariant BA.2".
The expert said it is "widely accepted" now that Covid "has lost its punch", but the immunity generated with the original Omicron variant is "not as good at preventing reinfection with BA.2".
"If you've been vaccinated and got Omicron, you'll still have a good level of protection against BA.2, but if you haven't been vaccinated, the chances are that you won't be protected against BA.2."
Prof Mills said the recording of the new variant makes the need for booster vaccines for children all the greater.
He said people who have been tripled vaccinated and have contracted Omicron have a high level of protection, but children who have only received two vaccine doses are unlikely to be protected against BA.2.
He said: "So, there is a case that I'm sure NIAC (National Immunisation Advisory Committee) will be looking at this now, and the authorities may decide to give a booster to that age group as well."
