Primary Navigation for the CDC Website
CDC en EspaƱol
Vaccine Safety
E-Mail Icon E-mail this page
Printer Friendly Icon Printer-friendly version
 Vaccine Safety Basics
bullet Information for Parents
bullet Why It's Important to Monitor Vaccine Safety
bullet How Vaccines Are Tested and Monitored
bullet Common Questions
bullet Vaccine Safety Concerns
bullet Questions About Vaccine Recalls
bullet Kawasaki Syndrome and RotaTeq Vaccine
bullet MMR Vaccine and Autism
bullet GBS and Menactra Meningococcal Vaccine
bullet Mercury and Vaccines (Thimerosal)
bullet Sudden Infant Death Syndrome
bullet History of Vaccine Safety

 Public Health Activities
bullet Vaccine Adverse Event Reporting System (VAERS)
bullet Vaccine Safety Datalink (VSD) Project
bullet Clinical Immunization Safety Assessment (CISA) Network
bullet Brighton Collaboration
bullet Vaccine Technology
bullet Emergency Preparedness
bullet Publications
bullet Scientific Agenda

Measles, Mumps, and Rubella (MMR) Vaccine and Autism Fact Sheet

Basic Information

  • The MMR vaccine protects children against dangerous, even deadly, diseases.

  • Because signs of autism may appear at around the same time children receive the MMR vaccine, some parents may worry that the vaccine causes autism.

  • Carefully performed scientific studies have found no relationship between MMR vaccine and autism.

  • CDC continues to recommend two doses of MMR vaccine for all children.

Additional Facts

  • MMR is a combination vaccine that protects children from measles, mumps, and rubella (also known as German measles). The first dose of the vaccine is usually given to children 12 to 15 months old. The second dose is usually given between 4 and 6 years of age.

  • In 1998, a study of autistic children raised the question of a connection between MMR vaccine and autism.

  • The 1998 study has a number of limitations. For example, the study was very small, involving only 12 children. This is too few cases to make any generalizations about the causes of autism. In addition, the researchers suggested that MMR vaccination caused bowel problems in the children, which then led to autism. However, in some of the children studied, symptoms of autism appeared before symptoms of bowel disease.

  • In 2004, 10 of the 13 authors of the 1998 study retracted the study's interpretation. The authors stated that the data were not able to establish a causal link between MMR vaccine and autism.

  • Other larger studies have found no relationship between MMR vaccine and autism. For example, researchers in the UK studied the records of 498 children with autism born between 1979 and 1998. They found:

    • The percentage of children with autism who received MMR vaccine was the same as the percentage of unaffected children in the region who received MMR vaccine.

    • There was no difference in the age of diagnosis of autism in vaccinated and unvaccinated children.

    • The onset of "regressive" symptoms of autism did not occur within 2, 4, or 6 months of receiving the MMR vaccine.

  • Groups of experts, including the American Academy of Pediatrics, agree that MMR vaccine is not responsible for recent increases in the number of children with autism. In 2004, a report by the Institute of Medicine (IOM) concluded that there is no association between autism and MMR vaccine, or vaccines that contain thimerosal as a preservative.

  • There is no published scientific evidence showing that there is any benefit to separating the combination MMR vaccine into three individual shots.

More Information

Other Organizations

*Links to non-Federal organizations found at this site are provided solely as a service to our users. These links do not constitute an endorsement of these organizations or their programs by CDC or the Federal Government, and none should be inferred. CDC is not responsible for the content of the individual organization Web pages found at these links.

Page last reviewed: October 22, 2007
Page last updated: October 22, 2007
Content source: Immunization Safety Office, Office of the Chief Science Officer

  Home | Policies and Regulations | Disclaimer | e-Government | FOIA | Contact Us
Safer, Healthier People

Centers for Disease Control and Prevention
1600 Clifton Rd, Atlanta, GA 30333, U.S.A.
Public Inquiries: 1-800-CDC-INFO (232-4636); 1-888-232-6348 (TTY)
USA.govDHHS Department of Health
and Human Services