Nearly 400 people have been diagnosed with mumps so far this year - including 62 in the Western region.
New statistics from the Health Protection Surveillance Centre show 64 new cases of mumps were reported nationally last week alone, bringing the total for this year to date to 381.
Just over 60 percent of cases were in young people aged 15 to 24.
115 of the cases so far this year were in the Eastern region, while just 9 diagnoses were confirmed in the South East area, and 62 in the West.
Some outbreaks have been reported in schools and universities, with Trinity College telling people to stay at home if they feel unwell.