An urgent plea to stop socialising and have a stay-at-home family Christmas has been made as Covid-19 surges, plunging the country into a third wave of the virus.
The call was made last night by Chief Medical Officer Dr Tony Holohan, who urged people not to go to restaurants or pubs.
It comes as fears that a new strain of the virus - which could be 70pc more transmissable - may be circulating, although no confirmed cases have been found here.
Dr Holohan and Professor Philip Nolan, who tracks the virus, said that although the new strain could not be ruled out, the dramatic jump in infections was due to pre- Christmas socialising.
An additional 727 cases were reported yesterday.
The country could be heading for 900 cases a day by the end of the month, and a critical daily toll as high as 1,300 by January 6.
"Our current disease trends are gravely concerning. The situation has deteriorated rapidly," Dr Holohan said.
"3,837 cases have been notified in the past seven days.
"The five-day rolling average has increased from 339 on December 17 to 616 on December 21, an 82pc increase.
"It is as important as it was in March to limit your contacts and protect your loved ones."
Prof Nolan said the virus is transmitting rapidly, "faster than we have seen at any point since March".
"The case numbers are growing at least 5pc to 7pc per day and, of particular concern, across all age groups," he said.
There was a significant rise in patients with Covid-19 in hospital yesterday, up to 241 after falling to under 200 in recent weeks. The number in intensive care is stable at 29.
There is a worrying increase in infections among people over 65 and over 85.
As in the first wave, these vulnerable groups are catching the virus early.
Dublin is now back in as bad a situation as it was in October before the last lockdown.
Dr Cillian De Gascun, of the National Virus Reference Laboratory, said the new strain "has not been detected in Ireland".
"But as we know, the variant has been circulating in the UK since September," he said.