A professor of immunovirology has said Ireland will not go back to where it was in January with the coronavirus.
UCC Professor Liam Fanning was speaking as figures show the Delta variant accounted for 20% of Irish cases last week.
Chief Medical Officer Dr Tony Holohan has raised concerns about the rising number of Delta cases here.
Prof Fanning told Newstalk Breakfast he believes Dr Holohan is concerned over hospitalisations.
"If we get large numbers of that age group - 16 to 40 infected - then undoubtedly some numbers will end up in hospital, and undoubtedly some numbers of them will end up in ITU.
"And maybe it's from that perspective, but our hospitals have an enormous capacity at this stage to handle a very large hospital requirement for COVID-19.
"And I don't see us actually, frankly, getting back to where we were in January - where we were overwhelmed - because we have vaccinated the vulnerable".
"I think, and I've used this phrase before, we had become paralysed at one stage of the notion of a 'variant this and variant that'.
"While understanding at the same time, then - and I can't square this off - that the vaccines gave us wonderful protection against all the variants that have arisen".
'End age-based access'
But he said the country should now do away with the age-based vaccine system.
"It perplexes me considerably as to why we are an outlier in lots of things to do with COVID - longest lockdown, lack of use of antigen tests.
"I think one of things that might assuage Dr Holohan's concerns is if the vaccination was open to everybody now.
"We've more or less done the over-40s, those who are going to get sick have been vaccinated more or less - except for that unfortunate few between 60 and 69 who are waiting on their second AstraZeneca.
"And you know my opinion on that: I think they should be just given Pfizer straight away, no delay whatsoever.
"By opening up the vaccine portal to those over 16 for Pfizer, 18 for Moderna, we target those individuals where the infection is running [higher].
"It's hard to get concrete data at the moment since the side effects of the hack, but it's safe to say that... the median range is in the high 20s to maybe the early 30s.
"And by opening up the vaccine portal, we give everybody an opportunity to be vaccinated.
"I think it's time we stopped this age-related access to this modern medicine".