The MMR vaccine protects against mumps and is part of the immunisation program in UK.
Mumps is a viral infection that causes the glands of the face (in front of the ears) to swell. The condition can be very painful and infectious (for a total of about 10 days). Your child will complain of tenderness and pain when chewing and will also find swallowing uncomfortable. There is no treatment for mumps but you must contact your GP if you think your child has mumps. Your GP will be able to treat any complications that develop along with the infection.
You can give your child paracetamol to bring the temperature (if any) down. As chewing will be painful, don't force him to have solids. Ensure that he has plenty to drink. Avoid juices as they are acidic and may hurt more by producing more saliva. A hot water bottle (placed under the cheek) may also help.
Occasionally, mumps can cause swelling of the testicles in boys and ovaries in girls.