Chief Medical Officer Dr Tony Holohan has said only half of people with Covid-19 symptoms are isolating.
The news comes after the Department of Health reported a further 4,799 Covid cases, with 467 people now in hospital, 104 of whom are in ICU.
In a statement, Dr Holohan said he is ‘concerned’ after receiving the latest data from Amarach, which shows just 50% of people with Covid symptoms are isolating.
He said: “It's also a concern that our latest Amarach tracking data shows that only half of people with symptoms are isolating.
“This is the single most important piece of basic public health advice - it is vital that you isolate as soon as you experience any symptoms of COVID-19 and arrange a PCR test.
“Do not meet up with others and put them at risk of COVID-19 or another respiratory infection. Do not rely on a negative antigen test as a basis for not isolating.”
Dr Holohan also asked young people to reconsider their social interactions over the Christmas period as a significant spike in cases among those aged 16 to 34 years old was recorded in the last seven days.
He said: “The level of disease and positivity rate amongst young adults has increased sharply in the last week.
“One in four people in the 16 – 34-year-old age group that are going for a PCR test have received a 'detecte' result. This is one of the highest rates since the beginning of the pandemic.
“This high level of disease in young people represents a high risk to those they come into contact with who have yet to be vaccinated or receive their booster. Therefore, if you have not yet received your booster you are best to avoid unnecessary contact with people outside your household. "
Tanaiste Leo Varadkar has also warned that high cases numbers will be recorded in the days ahead as the country struggles to stem the spread of the Omicron variant.
Speaking on RTE’s Morning Ireland, he said: “This is a more transmissible strain of the virus, so we will see very high case numbers, but we’re hoping and expecting that it won’t translate into hospitalisations and ICU admissions and deaths to the extent it did in previous waves.”
Mr Varadkar said the transmissibility of the Omicron variant could mean that those in hospital “may get it, but not be in hospital because of it”.
Asked about the possibility of further restrictions, Mr Varadkar said: “We have no plan to impose more severe restrictions before the new year or after it, but as the CMO said, we can’t rule it out… As everyone knows, the virus has surprised us on many occasions, and if we have to, we will do whatever it takes to protect human life.”
