Take-up of MMR jab has fallen after fears about its safety

They say 70% of 18 year olds could contract the disease, which has doubled its incidence in recent years.

Those most at risk were born before the introduction of the MMR vaccine in 1988 and probably escaped the illness in their childhood.

Health officials believe they could now be vulnerable to outbreaks of the disease on university campuses.

In April this year, an outbreak at Sheffield University affected 250 people. Ten needed hospital treatment.

Muscle aches

In children, mumps can cause complications such as viral meningitis.

But serious problems are likely for those after puberty who failed to be immunised by MMR.

The number of people in their late teens catching mumps has doubled in recent years.

Mumps is spread in saliva or in tiny droplets of fluid when someone coughs or sneezes.

Half of cases cause no symptoms at all, but those affected suffer fever, muscle aches and shivers.

The MMR take-up rate has fallen because of fears about its safety.