Booster jabs for people in their 50s will begin in late December or early January, HSE chief Paul Reid has said.
Mr Reid appeared before the Joint Committee on Health on Wednesday to discuss the pressures facing the Irish health system, fielding questions on PCR testing, intensive care capacity and the booster program.
He warned TDs and senators that the health system remains under “very serious pressure”.
It comes amid fears over its ability to cope in the face of a further surge in Covid-19 cases.
Mr Reid told the committee he expects people in their 50s to receive an invitation for a booster jab by the end of December or early January.
He said the booster program for those aged 80 and above has been largely completed, while more than half of people in their 70s have received an extra dose.
Mr Reid said the plan is to expand capacity to 270,000 vaccines administered a week, with the majority taking place in vaccination centers.
In his opening statement to the committee, Mr Reid said: “We are now firmly in the midst of a fourth surge in Covid-19 infections.
“The entire health system, both acute hospitals and community, are now under very serious pressure.
“Last Monday week I briefed the Cabinet Sub-Committee on Covid-19 on the seriousness of the situation.
“The Government responded with a number of public health measures.
“It has also been necessary for the HSE to take immediate measures in response to hospital and ICU pressures, including the short-term prioritization of unscheduled care, and increasing our surge capacity through providing additional beds, particularly in ICU.
“I know that the resurgence of the virus, and the response now required, will place even more pressure on staff.”
Another 3,666 cases of Covid-19 in Ireland were confirmed on Tuesday.
Chief Clinical Officer in the HSE, Dr Colm Henry, told TD Gino Kenny that intensive care bed capacity, following surge preparations, is currently at 300.
The plan, he said, is to expand this to 350.
Dr Henry confirmed eight intensive care beds in private hospitals are currently being used.
The senior medic warned: “That’s the big condition, here, it doesn’t come without a price. And the price is redeploying staff who are trained in this and also providing care outside traditional units.”
According to the latest figures, there are around 638 patients in hospital with coronavirus, 130 of them in intensive care.