What are the known complications of measles vaccination?
A. Measles vaccine is very safe; most people have no reactions. About 5 percent to 15 percent of vaccinees may develop a fever 5 to 12 days after MMR vaccination. The fever usually lasts one to two days and usually is not associated with other symptoms. About 5 percent of MMR recipients may develop a transient rash one to two weeks after immunization. Central nervous system disturbances, such as encephalitis, have been reported with a frequency of less than one per 1 million doses administered, a frequency many times lower than the incidence of serious central nervous system disorders that follow natural infection.
