MMR vaccine protects against three diseases, mumps, measles and rubella. The shots are generally given at age two, about the same age as symptoms emerge from autism. A 1998 study in England suggested that the MMR vaccine was linked to a perceived increase in the incidence of autism, a severe neurological disorder. The committee report, however, noted that many other studies on MMR and autism find no association. Additionally, the committee said there have been no animal studies linking MMR vaccine and autism and that suggested biological mechanisms connecting the vaccine and autism have not been proven in controlled studies.
Autism is a permanent neurological disorder.
Children with autism generally have difficulty communicating, may become obsessed with repetitive motions, such as head rolling, and often are intolerant of changes in their environment. They also may have learning difficulties. MMR vaccine shots are required in all 50 states before a child is admitted to public schools or day care centers. The vaccine has been credited with generally controlling the once-common childhood diseases. The number of measles cases, for instance, has dropped from about 400,000 a year to only 100 in 1999.