The National Immunisation Advisory Committee (Niac) is to recommend that the Johnson & Johnson vaccine can be used by those over the age of 50, The Irish Times understands.
The vaccine can also be used for those under 50 if another vaccine is not available, and for those in hard-to-reach circumstances where a single-shot vaccine is more appropriate.
It is also understood that Niac will change its recommendation for the AstraZeneca vaccine to allow it to be used by those over 50, significantly extending its use.
The chief medical officer, Dr Tony Holohan, and the Department of Health are understood on Monday evening to be awaiting formal notification of Niac's advice, which is expected to be delivered later on Monday evening or on Tuesday morning.
Once he receives it, Dr Holohan in turn will formulate advice based on the Niac letter for Minister for Health Stephen Donnelly.
Once the advice is approved and adopted by the Minister, the Health Service Executive is charged with putting it in place.
Some 605,000 doses of the Johnson & Johnson vaccine are due in the country before the end of June. Easy to transport, store and requiring a single dose rather than two, the vaccine has been earmarked for use among vulnerable populations such as the Traveller, homeless and Roma communities in particular.
Last week, the European Medicines Agency confirmed the benefits of the Johnson & Johnson vaccine outweighed the risks of blood clots as a very rare side effect. The unusual clots are extremely rare, occurring in just under one in a million recipients.
On Friday, it also reiterated the benefits of the AstraZeneca vaccine.
Earlier on Monday, one further death of a Covid-19 patient was reported by the National Public Health Emergency Team, bringing to 4,874 the total number of deaths in the pandemic.
Nphet also reported 437 confirmed cases of the disease, bringing to 247,069 the total number of cases in the Republic.
Of the new cases, 169 were in Dublin, 62 in Donegal, 40 in Kildare, 29 in Meath and 21 in Galway, with the remaining 116 cases spread across 17 other counties.
County incidence rate
The 14-day incidence of the disease now stands at 121 cases per 100,000 people nationally. Donegal has the highest county incidence, followed by Kildare. Kilkenny has the lowest incidence.
The median age of cases is 29 years and 76 per cent are under 45.
“As a country, we have now given a first dose of vaccine to 25 per cent of eligible adults,” Dr Holohan said. “In order to protect the vital work of the vaccination programme in offering us all protection from Covid-19, it is important we continue to remain vigilant and careful. Right now, we need to protect the progress we have made together.
"While we should remain cautious, we can also be cautiously optimistic. Our vaccination programme, alongside the continued commendable adherence of the vast majority of people in Ireland to the public health advice, are the key to exiting this pandemic in the coming months.
“However, doing things like mixing indoors when disease is still circulating at a high level puts our progress at risk. Please continue to act in the best interests of one another and be safe when socialising.”
On Monday morning, 184 Covid-19 patients were hospitalised, of which 46 were in ICU. There were 19 additional hospitalisations in the previous 24 hours.
Up to Saturday, 1,385,753 doses of vaccine had been administered: 987,681 people first doses and 398,072 people second doses.
Meanwhile, sports pitches, tennis courts, golf clubs and outdoor visitor attractions reopened on Monday. However, it is understood the Government will resist pressure to accelerate the planned summer reopening of the country amid concerns about a potential spike in Covid-19 infections.
Nphet will meet on Wednesday to consider its recommendations to Government in relation to restrictions. A Cabinet subcommittee will meet on the same day and a formal announcement on the plans for Covid-19 restrictions will be made following a special Cabinet meeting on Thursday.