What are the possible side effects of the measles, mumps and rubella vaccine?

Mild problems• Fever (up to one person out of six)• Mild rash (about one person out of 20)• Swelling of glands in the cheeks or neck (about one person out of 75)If these problems occur, it is usually within seven to 12 days after the shot. They occur less often after the second dose.Moderate problems• Seizure (jerking or staring) caused by fever (about one out of 3,000 doses)• Temporary pain and stiffness in the joints, mostly in teenage or adult women (up to one out of four)• Temporary low platelet count, which can cause a bleeding disorder (about one out of 30,000 doses)Severe problems (very rare)• Serious allergic reaction (less than one out of a million doses)• Several other severe problems have been reported after a child gets the MMR vaccine, including: Deafness; long-term seizures, coma or lowered consciousness; permanent brain damage. These are so rare that it is hard to tell whether they are caused by the vaccine.Source: U.S. Centersfor Disease Control and Prevention