People in nursing homes will be “practically fully protected” from Covid-19 by the end of the week, the HSE has said.
Vaccination of frontline health care workers will also be complete by the end of this week, while some 250,000 inoculations in the over-70s group will be complete by then.
In total, the HSE expects 750,000 vaccinations to be administered in the coming days.
HSE chief executive Paul Reid told a briefing on Thursday: “By the end of this week, we will have close to 750,000 vaccinations administered, and well over half a million dose ones completed already.
“We’ll have close to 250,000 vaccinations completed in the over-70s group, and we’ll have completed our frontline health care workers, and that will be closed, that process around vaccinating frontline healthcare workers.
“And practically fully protected all of those residing in nursing homes.”
He added: “So despite much the frustration which we understand, based on supplies to date, the impacts that we have seen to date are very significant, and the benefits we’ve seen are very significant from the vaccination programme.”
Mr Reid said levels of Covid-19 in nursing homes are at the lowest level that has been seen during the pandemic, even lower than in July when the country was seeing just 10 cases a day.
They have also seen the lowest level of infection in health care workers as a percentage of the total weekly cases.
Mr Reid said: “Now, what we’re experiencing is entirely collapsing levels of Covid infections taking place in healthcare settings.
“So we are seeing really strong benefits.
“As we move down to the prioritisation group and continue to do that, we know we are making a huge difference to number of serious illness and deaths right now.”
The vaccination rollout is to significantly ramp up over the coming months, with approximately one million doses expected to be delivered each month for April, May and June across all suppliers.
Mr Reid said it is expected that the Johnson & Johnson vaccine should also become available during Quarter 2 of this year.
While there are not yet any scheduled delivery dates for that vaccine, Mr Reid said he expects some to arrive in April, with increasing levels being delivered in June and July.
Next week the target delivery is between 95,000 and 105,000 vaccine doses.
Use of the AstraZeneca vaccine resumed this week following a pause in its usage over concerns that it was linked to blood clotting.
After receiving the all-clear from the European Medicines Agency last week, some 17,500 doses have been administered of the 30,000 that were missed during its suspension.
Chief clinical officer Dr Colm Henry said recent studies have shown “hints” that the vaccine can not only reduce serious illness and deaths, but could also stop transmission.
Citing a study in Scotland taken between December and March, he said: “In this study, which involved a lot of people, if you were unvaccinated and you lived with a vaccinated healthcare worker, you were much less likely (54%) to get Covid."