The HSE is advising of an outbreak of Mumps in the Western Region.
There's been an increase in the number of people aged 15-29 years old being diagnosed with mumps in the West, with 45 patients diagnosed in the past 7 weeks.
Mumps is an acute viral illness that causes fever, headache and swollen salivary glands, and can be spread from person to person by coughs and sneezes, as well as through direct contact with saliva.
People with mumps remain unwell for 7-10 days, and treatment of mumps is focused on relieving symptoms, with fluids and over the counter painkillers, as well as rest.
To prevent infection, people with mumps are advised to stay away from school, college or work for 5 days after the onset of their symptoms.
With 45 patients in the West diagnosed with Mumps in the past 7 weeks, this is considered an outbreak, according to the HSE, who say the best protection against mumps is to have the MMR vaccine.
If people have not had two doses of the MMR, or are not sure if they've had two doses, they should be vaccinated as the HSE says an extra dose of the MMR vaccine will not do any harm.