The HSE is raising concerns that up to 7-thousand children a year aren't being vaccinated against measles and mumps.
It comes as children across the country prepare to go back to school this week.
Over 1,600 cases have been recorded so far this year - that's three times the total in the whole of 2018.
The most significant outbreaks have been in the north west, with at least six cases linked to a single outbreak in Donegal.
Dr. Kevin Kelleher from the HSE says children need to get the MMR vaccine to be protected - but is worried take-up rates have fallen: