The Taoiseach has hailed "fantastic" healthcare workers as a major vaccine milestone is set to be hit later today.
Michéal Martin said that he was told by members of staff that over two and a half million doses will have been administered by the end of today.
This is despite the major issues surrounding the cyber attack on the systems in the health service.
Mr Martin tweeted: "Informed by the HSE that 2.5 million doses of the #CovidVaccine will have been given out by the end of today. A fantastic effort by all staff, volunteers and GPs involved in Ireland's vaccine rollout."
As of May 22, around 45% of Ireland’s adult population has had their first dose of a Covid vaccine, while just over 15% are now fully protected from the severe side effects of the disease.
The HSE also said that 300,000 Covid-19 vaccine doses were administered last week and that it expects to administer a similar number of doses this week.,
Currently people aged 45 and older have been granted access to the online vaccination portal to join the queue for their first dose.

An announcement will be due in the coming days on when vaccination registration for people aged 40-44 will open.
The groups currently being vaccinated against COVID-19 are:
- people aged 65 years and older who live in long-term care facilities (group 1)
- frontline healthcare workers (group 2)
- people aged 70 and older (group 3)
- people aged 16 to 69 who are at very high risk (group 4)
- people aged 65 to 69, including those at high risk (group 5 and 6)
- people aged 16 to 64 who are at high risk (group 7)
- pregnant women
Among the next to be vaccinated in line with the current plan is group 8, which encompasses residents of long-term care facilities aged 16-64 - as well continued vaccination for those who have signed up online.
The final group in Ireland’s vaccination rollout, group 9, will include people aged 16-64 living or working in crowded settings, and in parallel, and more generally, people aged 64 years and younger.