Mumps is a contagious disease that is caused by the mumps virus. Mumps typically starts with a few days of fever, headache, muscle aches, tiredness, and loss of appetite, and is followed by swelling of salivary glands. Anyone who is not immune from either previous mumps infection or from vaccination can get mumps.
Before the routine vaccination program was introduced in the United States, mumps was a common illness in infants, children, and young adults. Because most people have now been vaccinated, mumps has become a rare disease in the United States.