The National Public Health Emergency Team (Nphet) says that cluster was successfully contained because those who were infected stuck to the public health rules.
988 more people tested positive for Covid-19 in Ireland yesterday, and 26 more deaths were confirmed.
Professor Gerry Killeen of UCC says the P1 variant has shown how much of a threat the mutations can be, after causing a devastating second wave in northern Brazil.
Prof Killeen said: “What we see in surveillance is always just a part of the picture, I’m sure it is already in the country, it shouldn’t be a big surprise, and it is a genuine concern.”
“It’s not necessarily more transmissible or more virulent than the UK strain we’ve already got in the country,” he added. “If any population is known on this planet to have achieved or approached herd immunity it would have been Manaus but then it got hit a second time, and it was actually worse.”
Speaking yesterday, HSE chief clinical officer Dr Colm Henry said the newly-discovered Brazilian mutation of coronavirus in Ireland may be more transmissible.
Explainer: How dangerous is the new Brazilian Covi…
He told RTÉ Radio 1: “It may well be more transmissible.
“As to whether or not it is more resistant to the neutralising antibodies that is created by vaccines, we don’t know yet.
“We know from the South African variant that shares some traits that it has a greater resistance but is still susceptible to vaccines. But of course it is worrying.”
The Brazilian variant first emerged in July.