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 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 MMR Vaccine
bullet Mercury and Vaccines (Thimerosal)
bullet Questions About Multiple Vaccines
bullet Questions About Vaccine Recalls
bullet Fainting (Syncope) After Vaccination
bullet Kawasaki Syndrome and RotaTeq Vaccine
bullet GBS and Menactra Meningococcal Vaccine
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
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bullet Scientific Agenda

Measles, Mumps, and Rubella (MMR) Vaccine

Photo of infant's face

The measles, mumps, and rubella (MMR) vaccine is a combination vaccine that was licensed in 1971 to protect against measles, mumps, and rubella. These diseases are serious and can be potentially deadly. Each year in the United States, nearly 10 million doses of the vaccine are distributed. Due to high vaccination rates, outbreaks in the U.S. are not as common as before the mid-1960s. However, these diseases still appear in the U.S. and people who decided not to get the MMR vaccine are at risk of getting one or all three of these diseases.

Basic Information

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

  • Real risks of MMR vaccine are rare.

  • Most people who get the MMR vaccine do not have any problems, or "adverse events."

  • The most common adverse events following the MMR vaccine are pain at the vaccination site, fever, a mild rash, and swelling of glands in the cheeks or neck.

  • 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

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

    • This study had a number of limitations. For example, the study was very small, involving only 12 children. These are 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 study's 13 authors 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 United Kingdom 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.

  • A Vaccine Safety Datalink study found that the MMR vaccine rarely causes low blood platelet counts in children, which is not considered a serious complication. The study found no evidence of any serious complications.

  • A recent study found that measles outbreaks can occur in communities with a high number of unvaccinated people, and that maintaining high overall MMR vaccination rates is needed to continue to limit the spread of measles.

  • No published scientific evidence shows any benefit in separating the combination MMR vaccine into three individual shots.

More Information

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*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: August 22, 2008
Page last updated: August 22, 2008
Content source: Immunization Safety Office, Office of the Chief Science Officer

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