Measles is a very contagious disease caused by a virus. It spreads through the air when an infected person coughs or sneezes. Mumps is a contagious disease that is caused by a virus. Mumps typically starts with fever, headache, muscle aches, tiredness, and loss of appetite. Rubella is a contagious disease caused by a virus. It is also called German measles, but it is caused by a different virus than measles. Most people who get rubella usually have mild illness, with symptoms that can include a low-grade fever, sore throat, and a rash that starts on the face and spreads to the rest of the body. All can be prevented with the MMR vaccine.