One out of 10 children who catch measles will also have an ear infection or pneumonia. Measles can also cause an infection of the brain that could lead to convulsions, hearing loss, and mental retardation. This happens to about 1 out of 1,000 children reported to have the disease. Babies and adults who catch measles are often much sicker and more likely to suffer longer or die than elementary school aged children and teenagers with measles. This disease causes fever, headache, and swollen, painful glands under the jaw.
Mumps sometimes can be very serious disease.
Mumps can cause an inflammation of the coverings of the brain and spinal cord in about 1 person in every 10 who get it. Swelling or inflammation of the brain is reported in about 1 case out of every 200. Before there was a mumps vaccine, many children had hearing loss caused by mumps. About 1 out of every 4 teenagers or adult males with mumps will have a painful swelling of the testicles for several days. This usually does not make the person unable to father children.