The revelation comes amid warnings of a serious public health issue as it was confirmed that at least two, and possibly four, people have died nationwide and 62 people have been hospitalised with the illness.
The flu strain is affecting people in their 20s and 30s as well as traditionally vulnerable older age groups.
The HSE’s Assistant National Director for Public Health, Dr Kevin Kelleher, has revealed that a number of people have been admitted to hospital intensive care units with swine flu.
Flu activity increased during the last two weeks of 2018 and there are concerns that it will spread further as people return to workplaces and schools on Monday following the festive holidays.
Cork GP Dr Nick Flynn has urged people to get the flu vaccine to prevent further spread of the disease.