The Department of Health has confirmed 5,634 new cases of Covid-19.
There are 684 people in hospital with the disease, an increase of 16.
126 patients are being treated in ICU, which is up one since yesterday.
The Chief Medical Officer, Dr Tony Holohan, said this evening the "incidence of Covid-19 is continuing to rise, and today, we are once again reporting a concerning number of confirmed cases".
He said: "We know that every 1,000 cases of Covid-19 will lead to 20-25 people in hospital and between 2-3 people requiring critical care in ICU. We also know that, since June of this year, one in four people who had Covid-19 and required critical care in our hospitals have sadly passed away.
"This information is not easy to hear, but it is an important reminder of the serious risk that Covid-19 continues to pose to all of us."
Dr Holohan said that the department's latest research shows "almost 57% of people are reducing the number of people they plan to meet between now and Christmas and 45% have cancelled plans".
He said the data shows that "people are making a concerted effort to reduce their risk. If we can keep this going, it will have a positive impact on disease transmission".
In Northern Ireland, there has been a further three deaths of patients who had previously tested positive for Covid-19.
Another 1,469 positive cases of the virus were also notified by the Department of Health.
This morning there was 378 Covid-positive patients in hospital, with 36 in intensive care.
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Speaking earlier on RTÉ's Morning Ireland, Dr Holohan said: "We have a growing level of infection that need not happen. It is not inevitable that they will pick up this infection."
"If we get that behaviour, if you like, as good as it can be - cut down the people who are most likely to spread this infection from circulating in the population - we can have an impact in terms of transmission. Government can't make people do that."
Dr Holohan added that any improvements, as a result of fresh restrictions imposed last week, should begin to be seen this week and that NPHET will examine all the data when it meets later this week.
However, he added that it is unlikely that any significant changes will have happened.
NPHET will meet Thursday, Chief Medical Officer Dr Tony Holohan has said, adding that it's 'unlikely' they will expect to see a 'significant change' as a result of changes to restrictions introduced last week | Read more: https://t.co/gWfnQNH6AE pic.twitter.com/WMFIxUhodQ
— RTÉ News (@rtenews) November 22, 2021
Dr Holohan acknowledged that there are issues with capacity in ICU, but said Covid is a preventable respiratory infection and admission to ICU from a preventable disease should not be accepted.
Many countries across Europe, including Austria, have more ICU beds than Ireland but are still relying on restrictions to reduce the number of infections, he added.
The CMO also said that he would not be surprised if the National Immunisation Advisory Committee (NIAC) recommends expanding the booster vaccine to everyone under 50 and if that recommendation comes, it will come in good time.
He said antigen tests have always had a role, but their widespread use in asymptomatic populations needs to happen in situations where their use is understood.
He said around one in five adults reported using an antigen test last week and that they used them when symptomatic - which is not the public health advice.
When you have symptoms, you need to take a PCR test, he said.
There is a role for antigen tests, Chief Medical Officer Dr Tony Holohan has said, but cautioned that people who have symptoms of Covid-19 should take a PCR test rather than an antigen test | Read more: https://t.co/gWfnQNH6AE pic.twitter.com/xVNUIOWODx
— RTÉ News (@rtenews) November 22, 2021
He added that if an asymptomatic person wants to take an antigen test before a high risk activity (such as a wedding) then they can really only rely on the result if the result is positive.
Dr Holohan said he understands why the INTO believes ending testing and tracing in schools was a mistake, but added that there was clear evidence when schools resumed that test positivity in the primary school age group fell significantly in September, when there was a huge increase in testing among that age group.
Children in that age group, he said, are mostly picking up the disease at home rather than transmitting it in schools and that parents need to ensure that any child with a symptom stays at home, until they have a negative PCR test.
'Sending children into school with symptoms is a no-no' - Dr Tony Holohan says parents should not send children with Covid symptoms into school based on negative antigen test results | Read more: https://t.co/gWfnQNH6AE pic.twitter.com/FGsL1UiMNP
— RTÉ News (@rtenews) November 22, 2021
Critical care approaching 'saturation point'
Separately, the Dean of the joint faculty of intensive care at St Vincent's University Hospital in Dublin has said critical care is approaching saturation point across the State.
Dr Andrew Westbrook, a council member of the Intensive Care Society of Ireland (ICSI), said that more restrictions may be necessary in order to reduce pressure on hospitals, but that this is a matter for public health officials and the Government to decide.
He urged anyone who is eligible for vaccination or a booster shot to get it.
Elective procedures are being cancelled or postponed in all hospitals, he said, while elective diagnostic procedures for patients with chronic medical conditions, such as cancer, have been curtailed in order to prioritise the acute admissions for Covid and non-Covid patients.
Dr Westbrook said there has been a steady rise in Covid patients presenting at hospitals and between 5% to 10% of those will be admitted to intensive care. He described as "very unfortunate" the cancellation of a transplant surgery in the Mater Hospital and said it was symptomatic of the under resourcing of critical care beds in Ireland, adding that the healthcare system needs a minimum of 150 extra ICU beds.
People urged not to attend walk-in clinics for boosters without appointment
Separately, the Health Service Executive has said that walk-in booster vaccination clinics are not currently available, although they are being administered on some occasions.
The HSE said it was aware of a number of people who qualify for their booster turning up at vaccination centres, without appointment.
"Where there is local capacity and vaccine available, vaccination centres may endeavour to facilitate locally however, this will not always be possible," the HSE said.
As a result, the HSE has appealed to the public to wait for an allocated appointment by text and attend at their scheduled time.
A Covid adviser to the Irish College of GPs said she was aware that some people in their 60s and 70s are receiving booster shots at walk-in clinics, but said she would not encourage this because they are not guaranteed a shot.
Dr Mary Favier said GPs have almost completed administering boosters to the over 80s and are moving to the over 70s.
Speaking on RTÉ's Today with Claire Byrne, she also said antigen testing has a place in environments such as a workplace, but unfortunately they are being used too often in the wrong environment
Dr Favier said GPs are seeing people who are symptomatic doing antigen tests when they should be getting PCR tests and said she had a patient last week who had five negative results from antigen tests, but refused to believe he had Covid-19.
However, when he finally had a PCR test, he discovered that he did have Covid she said.
"The bottom line is if you've got symptoms, stay at home, isolate, get a PCR test, and only use antigen tests if you have no symptoms."
The HSE vaccination programme has now administered 580,017 booster, or extra doses, latest figures show. This includes 67,270 extra doses to people who are immunocompromised. The data is up to yesterday.
Additional reporting Fergal Bowers