Incidents of mumps jumped 15-fold in the last year, it was revealed tonight.
Health chiefs said many older teenagers have not been given the full double dose of the MMR vaccine, leading to an outbreak in schools and universities across the country.
Since the beginning of the year there were 1,957 incidents compared with 128 in the same period in 2008.
The Health Service Executive is offering post-junior cert children a free dose of the MMR vaccine to help ward off the debilitating illness, which could lead to meningitis.
Dr Brenda Corcoran, HSE national immunisation office, said: “This outbreak is happening because there are lots of older teenagers who have not had two doses of MMR vaccine and so are at risk of getting mumps.
“Outbreaks of mumps have been reported in secondary schools, colleges, universities, and sports clubs – that’s why we’ve decided to offer this group a dose of MMR.
“It will protect them now, and when they leave school.”
Mumps is an acute viral illness that causes fever, headache and painful, swollen salivary glands.
Sufferers can miss up to two weeks from school or work as the illness requires quarantine or isolation.
Generally complications are mild but mumps can cause meningitis, deafness or inflammation of the pancreas or testicles.
Teams from HSE Public Health Departments and Local Health Offices will contact second level schools across the country this week to schedule immunisation clinics at the schools.
The vaccine will be given to Transition 5th and 6th year students before the summer break.
Recent studies estimate that one dose of MMR is around 80% effective and estimates for two doses of MMR range from 88-95% effective in preventing the illness.
Health chiefs said if a young person’s MMR history is not known, an extra dose of MMR will do no harm and could offer valuable protection against mumps.