Almost 30% of COVID-related deaths that have occurred so far this year were related to outbreaks in hospitals or nursing homes, the Department of Health's chief medical officer has said.

According to Dr Tony Holohan, between January 1 and 15 of this year, 208 people had died as a result of COVID-19. Of these, 23 were linked to outbreaks in hospitals and 38 were linked with outbreaks in nursing homes - 29% overall.

"The ages of those who have died range from 25 to 98 years. Every death associated with COVID-19 is a tragedy. We must cut our social contacts in order to break the chains of transmission and protect those who are most vulnerable to this disease. Stay at home and save lives," Dr Holohan said.

According to Prof Philip Nolan, chair of NPHET's Irish Epidemiological Modelling Advisory Group, from an epidemiological perspective, this wave is different to what we have seen since last spring and is "perhaps worse".

"The penetration of the virus throughout all ages of the population is a particular cause for serious concern, as is risk of severe disease that all of these people face.

"Poor health outcomes, risk of serious or long-term illness and hospitalisation remain a risk for us all when it comes to COVID-19. That is why we must follow public health advice and protect not only ourselves, but our hospital system and healthcare workers by staying at home," he commented.

Responding to concerns about virus mutations, director of the National Virus Reference Laboratory, Dr Cillian De Gascun, pointed out that it is not unusual for viruses to mutate over time.

"We have identified multiple different SARS-CoV-2 lineages in Ireland since the start of the pandemic, and two of the three recently emerged variants of concern from the UK and South Africa. We also expect that more variants will emerge across the world in the coming months," he explained.

He said that while some of these new variants will increase the risk of becoming infected because they have increased transmissibility, in other words, they can stick longer and better to surfaces, "this does not mean that our continued adherence to the public health advice is in anyway less effective".

"We must continue to wash our hands, wear a face covering where appropriate, maintain our social distance and continue to adhere to the public health advice," he said.

A further 26 deaths were confirmed on Thursday evening, along with 3,955 additional cases. This brings the total number of deaths here to 2,488 and the total number of cases to 163,057.