At least 25 cases of the measles have been confirmed in midwest of the country since the beginning the year.
There were just 21 recorded cases of the measles in Ireland in 2017, according to The Irish Examiner.
The current outbreak is concentrated in Limerick city, where half of those with the illness have had to be hospitalised.
There has also been a confirmed case in Clare and in Dublin, both of which are thought to be linked to the Limerick outbreak.
The HSE said that the cases are mainly associated with the Ballinacurra Weston and Carew Park (Southill) area of the city.
Statistics show that immunisation uptake in Limerick city for the past few years has been consistently below the 95 per cent level recommended by the World Health Organisation (WHO).
It’s a serious public health issue, the Mid West Community Health team said in a statement.
Measles can spread rapidly, it warned. One person with the disease can infect 90 per cent of the people around them who have not been immunised.
Parents have been urged to make sure that their children get the MMR vaccine.
Meanwhile, figures from the INMO show that Limerick’s main hospital is currently under severe pressure from overcrowding.
University Hospital Limerick is today the worst in the country for trolley numbers, with 62 people currently waiting for a bed at the hospital.
Cork University Hospital is the second-worst with 38 patients waiting.
