Students leaving school and heading to university next month are being urged to make sure they are fully immunised against mumps as a major outbreak continues to blight the UK.
There are about 2,000 suspected cases of mumps reported by doctors in the UK each week, with rates well up on previous years.
And students are particularly at risk, as the infection spreads easily in environments such as colleges and universities.
The current epidemic is believed to be the result of young adults, who were too old to be routinely offered the measles, mumps and rubella vaccine when it was introduced in 1988, mixing with large numbers in university.
The Health Protection Agency is now appealing to school leavers who had not previously had two doses of MMR to ensure they are immunised before entering further education.
It is estimated that about 30 per cent of first-year students have not had two doses of MMR vaccine.
There have already been large outbreaks of mumps in several colleges and universities across the UK.
Figures for England and Wales from the HPA show there were 46,124 notifications of suspected mumps in the first 30 weeks of 2005.
This compared with 5,154 notifications during the same period in 2004 and 2,685 in
After lab tests, about 60 to 75 per cent of notifications for mumps are confirmed as genuine cases.
Dr Rosemary McCann, the HPA's immunisation leader in the North-west of England, said: "We have an unprotected cohort of older teenagers and young adults who missed out on the protection of two doses of MMR vaccine when they were young and these are particularly vulnerable.
"When these youngsters mix and mingle in close proximity in universities or further education colleges, we can have real problems.
"That is why I strongly support the call from university vice chancellors for school leavers who have not previously had the protection of two doses of MMR vaccine to ensure that they are vaccinated before going into further education this autumn."
Dr McCann said that mumps was a nasty disease which could have serious side effects, including deafness.
"MMR vaccine is safe, proven and effective and two doses will provide lifelong protection against mumps, measles and rubella," she added.
In May, experts writing in the British Medical Journal warned that the UK was "in the grip of a nationwide mumps epidemic".
They said the highest attack rate was in those born between 1983 and 1986, who were too old to be offered the MMR jab routinely, although some may have received one dose in catch-up programmes.