People will be able to receive a booster dose of a Covid-19 vaccine three months after their second dose under recommendations made by the National Immunisation Advisory Committee (NIAC).

The Minister for Health said he has accepted the NIAC recommendation.

Stephen Donnelly added that the booster doses will continue to be offered in the priority order previously recommended.

Those who received the Pfizer, Moderna or AstraZeneca vaccines had previously had to wait at least five months after their second dose before they were eligible to receive a booster.

The interval for those who received the single-dose Janssen vaccine was already three months.

The Department of Health has also said that NIAC has recommended a fourth dose of an mRNA vaccine three months after their third dose for those who are immunocompromised and for whom a third dose had been previously recommended.

More than 1.2 million doses of booster vaccines have been administered so far, latest figures show.

The HSE has said it expects 1.5m booster vaccines in total to be administered by Christmas.

Thousands of people were given Covid-19 booster jabs at walk-in HSE vaccination clinics across the country throughout the weekend.

Some had to queue for several hours to avail of the third dose of the vaccine, while other centres had little or no wait times, for those eligible for the jabs.

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Meanwhile there have been 4,688 new cases of Covid-19 reported by the Department of Health.

There are 518 people in hospital who have tested positive for Covid-19, up 14 from yesterday.

108 of these are receiving treatment in intensive care units, down one from yesterday.

Minister urges people to get booster vaccine

Minister Eamon Ryan has urged people to get the Covid booster vaccine, saying there are real and valid concerns because of the threat posed by the Omicron variant.

The full scientific analysis regarding the impact of Omicron on vaccines, on the severity of disease or on the transmissibility will not be known "for another week or two", he said.

But he said the basic message should still be the same that "we do need everyone to try to get that booster done, that will, it seems give further protection".

When asked on RTÉ's News at One if further restrictions could be ruled out, Eamon Ryan said they have learned never to rule anything out.

He said they will follow the science and look at what their European colleagues are doing, but added that on a positive note, the numbers in hospitals have stabilised in that last few weeks.

In relation to cancelling flights as happened last Christmas, Minister Ryan said that the World Health Organization and the European Centre for Disease Control has not advocated that approach.

He said they cannot completely lock off the country and they cannot seal off the risk, but they need to give time to get the boosters administered, to get as much protection as possible and to learn more about this variant.

Government Chief Whip Jack Chambers told RTÉ News that he does not believe more restrictions will be introduced before Christmas.

Professor Sam McConkey, a consultant in infectious diseases, said the best way to protect against the new variant is by deploying a huge rollout of booster vaccines.

Speaking on RTÉ's Six One News, he said he believes there is potential to administer more than half a million booster shots in a week by scaling up the programme and using pharmacies, GP surgeries, and more and larger vaccine centres working 12 hours, seven days a week.

The National Public Health Emergency Team will meet on Thursday to give its latest advice to Government, given the growing concern about Omicron.

534 patients on trolleys - INMO

The Irish Nurses and Midwives Organisation said that 534 patients are being treated on trolleys in hospitals across the country today, the highest number since the pandemic began.

The organisation called for bespoke plans to tackle overcrowding in each hospital.

INMO General Secretary Phil Ní Sheaghdha said: "Today's figures are a real nightmare before Christmas scenario.

"We need to see urgent mitigation measures from individual hospitals and the HSE to tackle the number of people on trolleys.

"We are once again calling for a fully-funded workforce plan, and adequate health and safety measures including enhanced ventilation in our hospitals," she said.

In Northern Ireland, the Department of Health has confirmed that four further patients who had previously tested positive for Covid-19 have died.

Another 1,431 cases of the virus were also reported today.

This morning, there were 309 Covid positive patients in hospital in Northern Ireland, of whom 32 were in intensive care.