Booster doses of the Covid-19 vaccine are to be offered to people aged 16-59 years who have an underlying condition.
They will also be offered to all residents in long-term healthcare facilities, irrespective of age, and those aged 50 to 59 years who have completed their primary course with any Covid-19 vaccine.
It follows new advice from the National Immunisation Advisory Committee (NIAC).
Minister for Health Stephen Donnelly said he will work with his department and the HSE to implement the recommendations as soon as possible.
Mr Donnelly has asked the HSE to look at ways of administering the booster vaccine to those with underlying medical conditions as quickly as possible.
Since the end of June to late October this year, eight out of ten people admitted to ICUs here had an underlying condition.
The Vaccine Taskforce is also set to return to oversee the booster programme.
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Taoiseach Micheál Martin has urged people to get their booster vaccines "in a timely manner" after what he said is "some evidence" that people are missing their appointments.
He told the Dáil that around 2.2 million people are now eligible for Covid-19 booster vaccinations.
The Fianna Fáil leader made the comments as he said he accepts the need to recognise the contribution made by under-pressure frontline healthcare workers.
Mr Martin said getting vaccinated is the best thing people can do for those who work in the health service.
Up to 1,500 people are turning up daily for their first vaccination, he said, "which shows that campaigns are beginning to penetrate and people are beginning to respond".
But he said there is also some evidence that people are missing their dates for their boosters.
"I would say to people who are eligible for their booster, who get a date for their booster, go please and get your booster in a timely manner."
Earlier, the co-leader of the Social Democrats, Róisín Shortall, said the roll-out of the booster vaccines has to be the priority.
Speaking on RTÉ's News at One, she said there has been very little information about when the various cohorts are likely to be vaccinated and said it would be helpful if people were told of the plan.
This morning, the HSE's director of acute hospitals said there is real concern about acute capacity in the hospital system and added that everything possible is being done to accelerate the booster campaign.
Liam Woods told RTÉ's Morning Ireland that NIAC's decision to expand the booster programme is being implemented through the HSE's vaccination programme and is progressing well.