The Department of Health has been notified of 1,380 new cases of Covid-19.
The number of people in hospital is 459, up 53 on yesterday.
There are 74 people being treated in intensive care for the virus, up three.
In Northern Ireland, 966 new cases were confirmed along as four further deaths were also reported.
HSE Chief Executive Paul Reid said there has been an increase of around 40% in Covid-19 hospitalisations in under three weeks.
Speaking on RTÉ's This Week, Mr Reid also said 40% of people in hospital with Covid are below the age of 65 and of those in ICU 65% are unvaccinated.
He added that Ireland is well ranked globally in terms of vaccinations and they are addressing the issue of those who are not vaccinated by looking at areas of low take-up levels.
"It is a constant campaign to get the unvaccinated forward."
He said there are mixed views from a health perspective on antigen testing but they do see a "value" in them and a role for them.
He said they are anxious to use them where it is appropriate.
"We are progressing the use of antigen testing in Third Level colleges, in childcare early learning settings and in a number of nursing homes."
He said the uptake of vaccinations among healthcare workers has been phenomenal and said all of them should have an obligation to get it.
We need your consent to load this rte-player contentWe use rte-player to manage extra content that can set cookies on your device and collect data about your activity. Please review their details and accept them to load the content.Manage Preferences
It comes as immunologist Professor Luke O'Neill said it is "disgraceful" antigen testing for Covid-19 is not being rolled out extensively as he raised the issue of PCR tests being "so slow" in terms of providing results.
"You will spot 80% of cases with antigen testing. It is a shame we haven't got them in every household."
He also said the over 60s should be given a Covid-19 booster vaccine as soon as possible.
Speaking on RTÉ's Brendan O'Connor programme, Prof O'Neill said the data from Israel is "compelling" and it would be effective to ensure people have further protection from the virus.
Four months into one of its worst Covid-19 outbreaks, Israel is seeing a sharp drop in new infections and severe illness, aided by its use of vaccine boosters, vaccine passports and mask mandates, scientists and health officials said this week.
Prof O'Neill said there should be a "rapid deployment of the booster campaign" as soon as the National Immunisation Advisory Council (NIAC) gives the green light to it.
He said he would recommend the Covid vaccine certs continue and that antigen testing would be useful to have also when nightclubs reopen.
"October 22nd is our next moment and they must reopen the nightclubs for definite. If we don't we are just keeping them closed to protect the unvaccinated."
He said it is about "preparing and getting on with things".
Minister for Social Protection Heather Humphreys, meanwhile, has insisted the Government is not against antigen testing and that it is something they are looking at.
She told RTÉ's The Week In Politics that an expert group will be providing advice to Government on the issue.
"It is all part of the solution. There is a number of different measures, whether it is Covid certs, boosters, antigen testing, we need to look at it all. And we will do that and we will give clarity on Tuesday."
Minister Humphreys also expects they will have advice from NIAC on the booster campaign by Tuesday.
She said it is evident it is working for other countries.
Minister @HHumphreysFG, says the government is concerned about the rising numbers of covid cases but says "we are not going back". Speaking on #rtetwip, she says the Gov will look at what they will do regarding the remaining restrictions, covid certs and booster vaccinations. pic.twitter.com/8m2LAaSxBH— The Week in Politics (@rtetwip) October 17, 2021
On the same programme, Labour's Aodhán Ó Ríordáin accused the Government of mixed messaging around antigen testing.
"I have heard cabinet ministers saying individually for a year they are not against antigen testing and yet nothing has changed in that space," he said. "The conversation needs to move on."
Public awareness campaign for young people to get vaccinated needs to be "ramped up" says Labour TD @AodhanORiordain. He says level of complacency of the virus has to be tackled again. #rtetwip rebroadcasts tonight at 22:00 on the RTÉ news channel and at 23:05 on @rteone. pic.twitter.com/IrV3fQC8Fg— The Week in Politics (@rtetwip) October 17, 2021
Separately, Director of the UCD National Virus Reference Laboratory said it is likely that Covid-19 case numbers will rise as restrictions ease, but this does not mean that vaccines are not effective.
Dr Cillian De Gascun, who is also a member of NPHET, posted a thread on Twitter last night, and said that vaccines are very effective at protecting against hospitalisation and severe disease.
His comments come as NPHET is set to meet tomorrow to discuss the latest surge in Covid-19 case numbers and make recommendations to Government ahead of the planned easing of measures on Friday 22 October.
Yesterday, the daily case number of 2,180 was the highest since January.
Dr De Gascun said that while the vaccines are preventing many people from getting seriously ill, they are not able to eradicate the spread of Covid-19 itself.
"Whilst vaccination reduces the risk of Delta infection, fully vaccinated individuals have viral loads similar to unvaccinated & can efficiently transmit infection in household settings, including to fully vaccinated contacts," he added.
Dr De Gascun said that that while vaccine uptake was high among those aged 12 and older, across the population as a whole around 75-80% of people are vaccinated.
"On that basis, and taking into account the cohort of the population that is not (yet, at least) eligible for vaccination, we can see that the current first generation of [Covid] vaccines is unlikely - in isolation at least, i.e. without additional public health measures - to be able to control [...] Delta in the community."
Hospitals preparing to scale up for surge capacity - INMO
The Irish Nurses and Midwives Organisation has said many hospitals across the country are preparing to scale up surge capacity for ICU because they are becoming full with patients due to Covid-19.
''People require ventilation support and preparations are being made to potentially deliver that outside of ICU,'' Edward Mathews, Deputy General Secretary Designate of the INMO, told RTÉ News.
He said the situation is deteriorating and there has been little improvement over the past fortnight.
''Delivering ICU care, outside of an ICU environment is not optimum,'' Mr Mathews added.
The INMO said many hospitals are also experiencing severe overcrowding in emergency departments and inpatient areas.
It said there are significant capacity issues in critical care.
''We are seeing a situation which is increasingly dangerous for both patients and staff,'' Mr Mathews said
The INMO said extra beds are required immediately in the private sector to alleviate the burden on the public service because the acute system is under pressure.
''That means taking patients out of public hospitals that can be cared for in private hospitals to leave them to deal with the acutely ill so that we have the space and safety to do that,'' Mr Mathews said.