Measles-Mumps-Rubella Vaccine and Autism

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At the request of the Centers for Disease Control (CDC) and Prevention and the National Institutes of Health, the Institute of Medicine (IOM), an arm of the National Academy of Sciences, evaluated whether the MMR vaccine causes autism. The IOM committee was an independent body that carefully examined the hypothesized MMR-autism link and addressed other vaccine safety issues.

The MMR vaccine protects against three different diseases (measles, mumps, and rubella) through one shot made up of three separate vaccines. The shot is given twice during childhood. The MMR vaccine has been very successful in making the serious and deadly diseases of measles, mumps, and rubella (German measles) very uncommon. For example, before the vaccine was given to children, there were about 400,000 measles cases reported each year in the United States but in 1999 there were only 100 cases reported.

Measles caused over a million deaths in children around the world last year, mainly in countries without widespread vaccination campaigns. A decline in the United States in the number of children vaccinated could cause an increase in the number of measles, mumps and rubella cases and sickness (such as pneumonia and brain damage) and even deaths. For example, before measles vaccines were introduced, 1-2 children out of every 1000 children who got measles died.

Autism is a severe and permanent developmental disorder. Children with autism mainly have problems interacting and communicating with others. Parents usually notice difficulties in language skills when their child is around two years old.

Autism is complex, and scientists are still trying to understand what causes it. Researchers believe that genetics play a big part in causing autism and that other medical or environmental factors may also be involved. Researchers believe that most cases of autism begin before or shortly after birth, although objective signs and symptoms show up several years later.

A small study in London in 1998 first raised the possibility that autism is linked to the MMR vaccine. While the study did not prove that MMR causes autism, it did increase the level of concern of many parents.

The question of whether MMR vaccine causes autism has also been raised because the number of cases of autism in the general population seems to be growing, and some parents have noticed the problems occurring soon after their child receives the MMR vaccine.

After reviewing all of the studies, including the study from London, which raised the possibility of an association between MMR and autism, the IOM has found that the evidence suggest NO link at the population level between MMR and autism. In fact, there is no clear evidence at all that the MMR vaccine causes autism. After evaluating all the evidence, the IOM committee supports the advice of pediatricians that people should continue getting their children vaccinated using the current recommended dose schedule.

It is important to understand that no vaccine is 100% "safe". Vaccines can cause minor side effects such as fevers or rashes and can sometimes also result in some serious side effects, just like medications. However, the MMR vaccine and all other vaccines have to pass safety testing required by the government before they are used. To learn more about the possible side effects of vaccines, please consult the CDC web site on vaccines.

To learn more about this issue, read the full report titled Immunization Safety Review: Measles-Mumps-Rubella Vaccine and Autism at From this website, you may also download copies of the FAQ, and report summary.