The Republic's government has announced strict new lockdown measures amid escalating hospital admissions and a record number of cases.
As Cabinet signed off on new restrictions today, a record 7,836 new cases of the virus were confirmed, with the chief medical officer warning of an incoming spike in deaths.
Schools are to close, most construction work will cease and new protocols on international travel were announced as part of the government's new suite of measures.
Business owners, such as pubs and restaurants, have been warned they may be closed until the end of March.
Taoiseach Micheál Martin said: "We simply have to suppress this surge and flatten the curve.
"Once again, the personal decisions that each and every one of us makes over the coming month will directly affect how many more people get sick and how many more people die."
The Taoiseach said that schools will close "from today, until at least the end of January" with teaching to move online.
But in a contentious move, already criticised by teacher's unions, Leaving Cert students will continue to attend three days a week. Read more
Final-year students will alternate their attendance for three out of five days each week.
On school closures, the Taoiseach said: "There will be two exemptions to this, special education should remain open with protections in place, and Leaving Cert students should continue to attend school for three days a week from January, the 11th."
"Leaving Cert students deserve the chance to sit normal examinations this year and, as a government, we will do everything we can to make that happen," he added.
Education Minister Norma Foley said she remains assured by public health officials that schools are safe, but would close "to minimise the movement of society".
She added: "The education sector is, generously I would suggest, making this a gesture, so as to support society in doing now what it needs to do."
Childcare services will close generally until the end of the month.
"They can remain open for vulnerable children and the children of essential workers," the Taoiseach said.
Other measures approved by Cabinet include closing non-essential construction from 6pm on Friday, and the end of click-and-collect services for retail outlets.
The Taoiseach said: "A special tribute must be paid to the construction sector and the construction unions, for the way in which they rose to the challenge of making sites Covid-safe.
"However the same considerations apply and all construction with a number of exemptions must cease until at least the 31st of January."
The government has also agreed to continue the ban on UK travel until midnight on Friday January 8, Transport Minister Eamon Ryan said.
From Saturday January 9, all passengers coming from the UK and South Africa will be required to possess a negative PCR test acquired within 72 hours of travelling.
Mr Ryan said: "They will have to present that negative test at the border management unit at an airport or at the ferry terminal.
"Failure to do so will be subject to either a fine of 2,500 euro or up to six months imprisonment penal provision, to make sure we get compliance."
The provision is certain to remain in place until at least January 31, he said.
The same measure will apply to travellers from other countries in the coming weeks, Mr Ryan added.
The Taoiseach has acknowledged there is a "problem" with people potentially circumventing Ireland's new travel measures by travelling from Great Britain into Northern Ireland and then across the open border.
He said: "That is a problem. There will be engagement and continuing engagement with the Northern Ireland Executive on this, but it's not easy.
"They are two different jurisdictions and two different political executives and set-ups, and therein lies the challenge."
He added there was a greater deal of alignment now between Northern Ireland and the Republic on public health issues than there had been "for some time".
Mr Martin said the latest data showed the UK variant of the virus had been detected in 41% of Covid-19 positive cases in people who had travelled from the UK in December.
Tanaiste Leo Varadkar said the government will act to "cushion the blow" another lockdown will have on people's livelihoods.
Support schemes such as the pandemic unemployment payment and the employment rates scheme will be extended until March 31.
But he warned business owners that they are likely to be closed until the end of March.
The Tanaiste said by the end of the month between 450,000 and 500,000 people could be claiming the pandemic unemployment payment (PUP).
Mr Varadkar said that figure compares with 250,000 people being in receipt of the payment in early December.
"If I was running a business now, I would be thinking that it is a probability that I would be closed until the end of March," he said.
Finance Minister Paschal Donohoe and Public Expenditure Minister Michael McGrath will engage with the banks to "ensure that they provide additional payment breaks to mortgage holders and people who have loans who cannot afford to make those payments", the Tanaiste said.
The Taoiseach also urged the public to forget about having takeaway pints.
Mr Martin said: "Forget about takeaway pints and takeaway alcohol. No publican should be selling takeaway pints.
"This is a very serious situation we are in. It leads to congregation, gathering of people, which can spread the disease."
The Taoiseach urged the public to bear in mind why the Government is taking these measures.
He said: "The study by London's Imperial College suggests that the new strain increases the number by between 0.4 and 0.7, which can rapidly lead to growth well beyond previous worst-case scenarios.
"That is why we are doing this. That is why we must dig deep within ourselves and face the coming month with steely determination and resolve."
He warned people not to let their guard down in the fight against the coronavirus.
He said: "We now have a vaccine and it is being safely distributed as quickly as we receive it. We welcome the news today that a Moderna vaccine has now also been approved.
"But please believe me when I tell you that, notwithstanding the vaccine rollout, truly enormous damage can be done if we let down our guard against the virus in any way in the time ahead."
Today brought a record 7,836 new confirmed cases of the disease, and an additional 17 deaths.
There are now 954 Covid-19 patients in Irish hospitals. The number of people in intensive care units with the disease is now 88, an increase of 12 in the past 24 hours.
There were 105 additional hospital admissions in the past 24 hours.
Chief medical officer Dr Tony Holohan said: "There is concerning escalation of admissions to hospital and ICU. We are very likely to see escalating mortality and ICU admissions in the coming days and weeks.
"It has never been more important, throughout our experience of this pandemic, to stay home and only meet people outside of your household for essential purposes, always adhering to public health advice; physical distance, hand hygiene, cough/sneeze etiquette, wearing a face covering."
Read more: Negative Covid-19 test needed for passengers from Britain and South Africa
