Autism and Immunizations

Over the last decade, many people have become worried autism and immunizations – they are concerned that immunizations may cause autism. There has been particular concern about the possible side effects of the MMR (measles, mumps and rubella) vaccine and particularly that it might cause autism.

There is no evidence that MMR or any other immunization causes autism, but more importantly, there is strong evidence that MMR does not cause autism and no other immunization causes it either. This page will answer in more detail, any concerns you may have about the autism and immunizations.

This page answers the following questions:


Why has MMR immunization been linked to autism?

In 1998, a paper was published in London that described 12 children (yes, only 12) who had autism and bowel disorders. It was only suggested that measles was related to the autism and the bowel disorders in these children, but comments in the paper lead the media to conclude that there was a link between the autism and immunization with MMR. This study has since been heavily criticised for causing such misinformation and most of the authors themselves have distanced themselves from the findings of the study. It has also recently been removed from the journal given the fact that the paper misrepresented its findings by suggesting a link between MMR and autism. The main author has been struck off the medical register for fraud committed in producing this paper.


However, the media made a big thing of this study especially a link between autism and immunizations. It was reported in the media that:

  • autism rates had increased since the introduction of MMR
  • MMR vaccine lead to regression of milestones in children
  • MMR caused a form of autism associated with bowel disorders
  • MMR, but not the single vaccines of measles, mumps and rubella, overwhelms the immune system

None of these suggestions have any factual basis and each is addressed more fully below. The widespread view by health professional that the results reported in this paper were not true, as has been subsequently found, did not make as many headlines in the press and as such people are still misinformed by believing that MMR and autism are linked.

The other reason that many people associate autism with MMR is that autism is often diagnosed in the second year of life – that is when many of the features stand out – and the MMR vaccine is given in the second year of life.

It is understandable that parents may want to link the autism and immunizations as they try to understand their child's condition, but the fact is that it is merely coincidence that autism diagnosis and MMR immunization occur about the same time. There have been many studies in many countries that have all shown the same thing – you are no more likely to get autism if you have the MMR vaccine than if you don't. There are no validated reports linking autism and immunizations.

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Have autism rates increased since MMR introduction?

It is true that autism rates are increasing but it has nothing to do with the MMR vaccination or other immunisations. Even before the MMR vaccine was introduced, autism rates were increasing and they have continued to rise even after MMR vaccination was introduced. And even in countries where MMR immunization was removed, (eg. Japan), autism rates have continued to rise.

Studies in 10’s of 1000’s of children have shown that you are no more likely to get autism if you have had MMR than if you have not. If your child is going to get autism, it is not from MMR.

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Does MMR lead to regression in milestones?

Some children with autism get regression of their milestones. Extensive studies, again of 10’s of 1000’s of children, have shown that you are no more likely to have autism with regression if you have the MMR vaccine compared to if you don’t have the vaccine.

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Is autism associated with bowel problems?

No. In a study of over 200,000 children, there was no difference in bowel symptoms in children with autism and those who did not have autism.

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Does having the single MMR overwhelm the immune system?

No. In countries where they have given the single vaccines (so measles, mumps and rubella all given separately), there has been the same rise in autism as in other countries. Studies have also shown that the immune system can easily handle all the immunizations we currently give to infants and children. There is no advantage of giving the measles, mumps and rubella vaccines separately.

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Does mercury in vaccines cause autism?

No. In the past, some vaccines contained thiomersal (thimerosal in the US) as a preservative. A huge study in Denmark showed that there was no increase in autism after pertussis immunization – at the time of the study pertussis vaccines contained thiomersal (thimerosal).

Most countries now use vaccines that are free of thiomersal (thimerosal), so there really is no need to be concerned about autism and immunizations containing mercury as it is not an issue.

To read more about the childhood immunization schedule, click here.

To read about the how immunizations work, click here.

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If you want to read up further about autism and the many myths surrounding it, the go to the Autism Watch website which comprehensively answers many questions surrounding autism and in particular, surrounding autism and immunizations.



  • eBandolier Apr 2005. MMR Vaccination and Autism.
  • Offit et al. Addressing Parents' Concerns: Do Multiple Vaccines Overwhelm or Weaken the Infant's Immune System? Pediatrics Jan 2002.109:124-129

To go to the top of the autism and immunizations page, click here

To go to the Measles and MMR page, click here

To read about immunization side effects, click here

To read about the how immunizations work, click here

To go to the Infant Immunization Schedule page, click here

To go to the main Immunization page, click here

To go to the Infections page, click here

To return Home, click here

Last reviewed 17 May 2011

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Dr Maud MD

Dr Maud MD (MBChB, FRACP, FRCPCH), a specialist pediatrician, provides health information and medical advice for parents of babies and toddlers. Read more about Dr Maud.

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