Eight counties in Ireland now have a 14-day incidence rate of over 150 per 100,000 people after the recent spike in cases.
A further 764 infections were confirmed on Sunday, with Chief Medical Officer Dr Tony Holohan expressing serious concern about the situation.
Donegal remains the county where the virus is most rampant with an incidence rate of 263.8 per 100,000 people.
Louth follows closely in second with a rate of 235.1, while Kilkenny (197.5) and Carlow (195) are the other worst hit areas of the country.
Laois, Cavan, Wexford and Limerick are the other four counties with an incidence rate of above 150, according to the Department of Health's latest data.
Leitrim and Clare both have the best rate's in the country with less than 30 per 100,000.
Dr Holohan warning
Speaking on Sunday's figures, Dr Holohan suggested that anyone who has been socialising in recent days and weeks should consider cancelling their Christmas plans.
He said: “Every indicator of disease severity is moving in the wrong direction, more rapidly than we had anticipated. We have particularly strong concerns about the prospect of inter-generational mixing around the festive season.
"On 11th December the 7-day incidence rate for people aged 19-44 was 106 per 100,000 population, by yesterday this rate had more than doubled to 217 per 100,000.
"If these younger people come into contact with their loved ones over the age of 65, we could see a spike in infections in this more vulnerable group. This would lead to very a serious pattern of disease, hospitalisations, ICU admissions and unnecessary deaths.
“If you have been socialising in the past few weeks or over this weekend, consider your Christmas plans carefully. Is it responsible to meet with your family over 65 later this week, if you have not kept your contacts low? Should you cancel your plans?
"We have the very real prospect of COVID-19 vaccines on the horizon. Ensure that your loved ones stay alive to receive them, by keeping your distance from them if you have not restricted your movements to this point.
"As difficult as it may seem, staying away from older family this Christmas will protect them - and it would be an exceptional sacrifice made for the common good.”
