Taoiseach Micheál Martin has reaffirmed the Government's target of ensuring that 80% of adults either receive their first Covid-19 vaccine, or are offered one, by the end of June.
Replying to Labour leader Alan Kelly in the Dáil, Mr Martin said: "The target is still the target."
He also clarified that the National Immunisation Advisory Committee (NIAC) will meet tomorrow to consider the latest advice from the European Medicines Agency.
The EMA said yesterday that the benefits of the single-shot Johnson & Johnson vaccine outweigh the risk of rare clots that have been linked to the jab.
Mr Kelly contended that "speed is of the essence" when it comes to the vaccine roll-out and NIAC needed to meet urgently.
"Every day counts," he said.
The Tipperary TD said he accepted that supply of vaccines is "clearly an issue", but he expressed concern at the "haphazard" way the Government was dealing with the project.
He said he was also worried about the establishment of large vaccination centres and the recruitment of vaccinators, something he claimed had been "a mess from the beginning".
In reply, the Taoiseach said that the vaccine roll-out programme has been "very effective", with a big impact on reducing mortality and severe illness.
He said this "very significant" impact was visible in places like nursing homes and the reduction of illness among frontline workers.
The Taoiseach said Ireland's relationship with AstraZeneca has been "challenging from the get-go", but he believed that the situation with vaccine supply can "improve significantly" if the Johnson & Johnson vaccine is made available.
He said NIAC would meet tomorrow to consider its advice on the matter.
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Also speaking at Fianna Fáil's parliamentary party this evening, Mr Martin said children and teenagers are likely to be vaccinated against Covid-19 after the adult population, once this is approved by regulators.
He said the EU Commission is pre-purchasing vaccines to deal with variants, as well as booster doses, for 2022 and 2023.
He said supply shortfalls with AstraZeneca that have emerged in recent days will not have an impact on reopening plans.
Tánaiste Leo Varadkar has also reiterated his belief that the Government can meet its target of giving a first dose, offering one, to 82% of adults by the end of June.
He told Fine Gael's parliamentary party this evening that two issues could prevent this from happening - either a lack of vaccine supply from drug companies, or people not taking the vaccine as case numbers drop.
He said Ireland needs to have at least 80% of the population fully vaccinated before the next winter.
At the meeting, there was some strong criticism of the performance of Health Minister Stephen Donnelly.
146,000 people between the ages 65 and 69 years old have registered for Covid-19 vaccination appointments through the HSE online and phone line registration portals since they were opened on Thursday last week.
This equates to just over 83% of those in this age group who were not already included for vaccinations appointments in earlier cohorts which included residents or staff of nursing homes, healthcare workers, and medically vulnerable people.
The HSE online and phone line vaccination booking facilities remain open for this age group.
About 40% of the bookings made by people in this age bracket over the past two days were made through the call-centre phone number. That was up from 10% during the first five days of the operation of the booking portal.
It is expected also that these booking facilities will be extended to the 60-64 age group later this week or early next week.
It will start on the first day with 64 year olds, the following day with 63 year olds and so on each day until 60 year olds are included.
NIAC to discuss J&J vaccine
The National Immunisation Advisory Committee is to meet tomorrow to consider issues relating to the Johnson & Johnson vaccine and the question of having a longer interval between the first and second doses of some vaccines.
The first batch of the J&J vaccines, amounting to 14,400 doses, is with the HSE. This first batch arrived last week. further 26,000 doses are due by the end of the month, the HSE has confirmed.
NIAC has already recommended that the AstraZeneca Vaccine should not be administered to people under the age of sixty in Ireland.
If a similar recommendation to that is made by NIAC in relation to the Johnson and Johnson vaccine could have implications for the pace of the vaccine rollout in the months ahead.
The state is currently receiving regular weekly deliveries of the Pfizer vaccine amounting to 130,000 doses per week. These regular deliveries are scheduled to increase to 215,000 doses per week during May.
However, last week the European Commission brokered a new deal to bring forward Pfizer deliveries from the fourth quarter of this year into the current quarter.
As a result, Ireland's weekly deliveries from Pfizer will now be boosted by an additional 50,000 doses each week starting on the last week of April.
NIAC is also considering whether or not the gap between the first and second doses of the Pfizer vaccine could be extended from the current gap of four weeks to perhaps six or eight weeks.
Any such extension of the time gap between doses could enable first-dose vaccinations to proceed a little faster for a period of time.
Meanwhile, the Senior Medical Officer with the Health Products Regulatory Authority has said there are some blood tests available that can quickly identify the rare blood clotting event linked to a small number of people who have received the AstraZeneca or Johnson & Johnson (Janssen) vaccine.
Speaking on RTÉ's Today with Claire Byrne, Dr Donal O'Connor said that following on from another more common syndrome where platelets were attacked in response to a blood thinner, doctors have checklists for certain types of blood thinners to use that would be beneficial in those who develop these rare side effects.
He said there are also special immune treatments to stop the clotting process.
Additional reporting George Lee