Measles, mumps, and rubella are all potentially deadly viral diseases.
Measles
Measles starts as a fever, cough, runny nose, conjunctivitis (pinkeye), and a red, pinpoint rash that starts on the face and spreads to the rest of the body. If the virus infects the lungs, it can cause pneumonia. Measles in older children can lead to inflammation of the brain, called encephalitis, which can cause seizures and brain damage.
Mumps
The mumps virus usually causes swelling in glands just below the ears, giving the appearance of chipmunk cheeks. Before the vaccine, mumps was the most common cause of both meningitis (inflammation of the lining of the brain and spinal cord) and acquired deafness in the U.S. In men, mumps can infect the testicles, which can lead to infertility.
Rubella
Rubella is also known as German measles. It can cause a mild rash on the face, swelling of glands behind the ears, and in some cases, swelling of the small joints and low-grade fever. Most children recover quickly with no lasting effects. But if a pregnant woman gets rubella, it can be devastating. If she’s infected during the first trimester of pregnancy, there’s at least a 20% chance her child will have a birth defect such as blindness, deafness, a heart defect, or intellectual disabilities.
The Measles, Mumps and Rubella (MMR) vaccine is recommended for children 12 months of age and older, and adolescents and adults born during or since 1966 who have not received 2 doses of measles-containing vaccine.
Reference
WebMD. (2020). Measles, Mumps, and Rubella (MMR) Vaccine. https://www.webmd.com/children/vaccines/measles-mumps-and-rubella-mmr-vaccine#1