Welsh health minister Edwina Hart has stated confidence needs to be restored in parents to encourage them to have their children immunised against mumps.
One of the most effective forms of protection is from the combined measles, mumps and rubella vaccine ? the MMR, she noted.
However, media attention at one point cast doubt over the safety and efficacy of the treatment, meaning some youngsters have not received one or both doses of the vaccine, Ms Hart added.
Recent figures showing the number of children who have received the treatment are "encouraging", but there is still a minority group who need encouragement to make sure their offspring receive the protection, she noted.
To increase the uptake of the vaccine in Wales, a DVD about immunisation is being redistributed to families and a leaflet has been published to remind the public of the dangers the illnesses can bring.
Ms Hart commented: "We need to restore the confidence of the minority of parents whose unvaccinated children enabled measles to become re-established as an endemic disease."
According to figures from the NHS, one in four males who catch mumps over the age of 12 might develop orchitis, which could lead to infertility.See all the latest jobs in Medical Devices