Video report by ITV News Correspondent Martha Fairlie
There were 5,042 recorded cases of mumps in England in 2019 – four times the number in 2018 and the highest level in a decade.
Many of these cases were as a result of outbreaks in universities and colleges and most were in young adults who did not have the MMR (measles, mumps and rubella) jab.
A large number of the 2019 cases were people born in the late 1990s and early 2000s who missed out on the MMR vaccine when they were children.
In 1998, doctor Andrew Wakefield led a study that linked the MMR vaccine to autism.
His work was subsequently discredited and he was struck off, but uptake of the vaccine dropped to about 80% in the late 1990s and a low of 79% in 2003.
Public Health England (PHE) is urging people to have both parts of the MMR vaccine, saying the full two doses are needed to maximise protection.
The vaccine prevents most, though not all, cases of mumps.
There were also increases in mumps cases in Scotland and Wales last year.
Dr Vanessa Saliba, of PHE, said it it never too late to catch up on immunisation.
“We encourage all students and young people who may have missed out on their MMR vaccine in the past to contact their GP practice and get up to date as soon as possible,” she told the BBC.
What is mumps?
Public Health England teams describe mumps as a contagious viral infection caused by a paramyxovirus. Swelling of the parotid glands is the most common symptom of mumps. The parotid glands are a pair of glands responsible for producing saliva. They're located in either side of the face, just below the ears.
More general symptoms often develop a few days before the parotid glands swell. They include:
mild abdominal pain
loss of appetite
a high temperature (fever) of 38C (100.4F), or above
If you have mumps, you can help prevent it spreading by:
regularly washing your hands with soap and water
using and disposing of tissues when you sneeze
avoiding school or work for at least five days after the onset of swelling