Professor Luke O'Neill has said it is "likely" that there will be a new Covid-19 vaccination campaign in the autumn for a fourth or fifth shot.
Covid-19 cases in Irish hospitals have rose rapidly over the past two weeks, with 360 patients hospitalised as of this morning.
Professor O'Neill is part of the new Government's Covid-19 Advisory Group and told Newstalk that they are planning for the autumn.
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He said: "The big question is come September, October will we see a big spike, because we're back indoors again and this spreads indoors.
"CAG as it's called, the Covid Advisory Group, is very much planning for what's going to happen in the autumn.
"It's likely there will be another vaccination campaign, a fourth or fifth shot."
Professor O'Neill said a newer vaccine could be used in the campaign.
"It could be one of the newer vaccines because Moderna - just published yesterday - they've got an Omicron-specific vaccine that got a massive response in the trial," he said.
"They're claiming an eight-fold improvement on their previous vaccine, based on measuring antibodies and so on.
"I'd like to see the data; but still, if that's true, that Moderna vaccine could be the one that we'll use in the autumn.
"It's the job of NIAC to advise on this, so they'll be looking at all this data".
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