FLU deaths have more than doubled as doctors report a sharp rise in the numbers of people falling victim to the virus in the last week.
There were five deaths confirmed in the first week of February – up from two the previous week, according to new laboratory figures.
The HSE Health Protection Surveillance Centre is urging high-risk groups to get vaccinated against the flu saying it is not too late in the season to receive the jab.
Flu rates have risen from 20.5 per 100,000 population to 32.4 per 100,000 population during February and are now "above threshold levels".
This means that flu is actively circulating in the community, warned Dr Joan O'Donnell, one of the the watchdog's specialist in public health .
She said: "It is still not too late for people who are at risk of the complications of flu to get vaccinated against the disease if they have not already done so.
"The vaccine is available free of charge from GPs for all people in at-risk groups, and from pharmacists for everyone aged 65 and over. An administration charge may apply to people who don't hold medical cards or GP visit cards."
The most recent flu surveillance report for February 3-9 revealed 23 patients with flu were admitted to intensive care so far this winter and 82 have been hospitalised.
High-risk groups are: l All those aged 65 years and older.
* People, including children with chronic illness requiring regular medical follow-up such as chronic lung disease, chronic heart disease, chronic neurological disorders, neuro-developmental disorders and diabetes
* Those with lower immunity due to disease or treatment
* All pregnant women. The vaccine can be given at any stage of pregnancy.
* People who are morbidly obese with Body Mass Index of more than 40.
* Residents of nursing homes, old people's homes and other long-stay facilities
* Health care workers and carers of those in risk groups.
Dr O' Donnell said: "The symptoms of influenza usually develop over a matter of a few hours and include a high temperature, sore muscles, dry cough, headache and sore throat. This is different from the common cold, which tends to come on more gradually and usually includes a runny nose and a normal temperature.
"Anyone who gets flu should stay at home, rest, drink plenty of fluids and use over-the-counter remedies like paracetamol to ease symptoms. Anyone in one of the high-risk categories should contact their GP if they develop influenza symptoms.
"Covering your nose and mouth with a tissue when you cough and sneeze, disposing of the tissue as soon as possible and cleaning your hands are important measures in helping prevent the spread of germs and reducing the risk of transmission."