Does the MMR vaccine cause autism?

There is no link between the MMR vaccination and autism (autistic spectrum disorder)

Many high quality scientific studies involving hundreds of thousands of children who have been vaccinated with the measles, mumps and rubella (MMR) vaccine have been carried out worldwide over more than a decade. None of these studies has found any link between the MMR vaccine and autism (or inflammatory bowel disease).

The exact cause of autism is still unknown. What is known is that there is no evidence that the MMR vaccine causes autism. This conclusion was reached after in-depth reviews of all the available information were conducted by the World Health Organization, and by scientific and medical experts in independent medical organisations in the UK, USA, and Canada.

Further evidence against any link between vaccines and autism comes from a recent US study. The study involved about 1,000 children, including 256 with Autism Spectrum Disorder. The researchers found that the total number of vaccines a child has before the age of 2 years makes no difference to their risk of developing autism. The number of vaccines given on a single day also makes no difference. This study indicates that multiple vaccines given at an early age does not increase a child’s risk of autism.

How did the MMR and autism controversy come about?

Rumours about the safety of the MMR vaccine were started in 1998 by a British doctor.

His research suggesting a link between the measles virus and autism was first published in a leading scientific journal, attracting a lot of attention. The research was later found to have serious flaws in the way it was conducted:

  • it was not known if the children studied had actually received the MMR vaccination
  • no information was given about how the children were chosen (bias)
  • only a very small number of children were studied
  • there was often no comparison group.

All these flaws meant that the findings are not reliable. The studies have since been discredited by experts.

The respected journal that had originally published one of the reports took the very unusual step of retracting the report because it had been proven to be dishonest and irresponsible research. After an independent investigation in 2010, the British authorities withdrew the doctor’s license to practice medicine in the UK. He was found to have broken research rules and to have acted unethically.

Since then, other researchers using more reliable methods have conducted more than 20 scientific studies to investigate a link between MMR and autism. None of these studies have been able to repeat the doctor’s results. In fact these studies have shown that there is no evidence at all of a link between MMR and autism. This suggests that the doctor’s conclusions were wrong.

Unfortunately, the concerns about vaccinating with MMR created by the discredited studies means that MMR vaccination rates in the developed world have dropped, leading to large increases in measles cases. For example, in the UK in 2011, there were ten times more measles cases than in 2010. In Australia, nearly all cases of measles are caught overseas by people who have not been vaccinated and ‘brought’ back home.

Deciding about having the MMR vaccination

Concerns about the unproven effects of the MMR vaccine have influenced some people not to vaccinate their children. While vaccination is a choice and is not compulsory, it’s worth understanding the true consequences of not being immunised versus the small risks associated with having the MMR vaccination.

Not having the MMR vaccination can have serious consequences for your child and others

Not vaccinating your child not only puts them at risk of getting measles, mumps or rubella, but also puts other people who have not been vaccinated at risk of infection and of the serious complications of these diseases (including birth defects in unborn babies).

  • Being vaccinated against these diseases protects not only your child from infection (i.e. makes them immune), but also protects everyone in the community, by reducing the number of people who can catch the infections and pass them on to others. This is called 'herd immunity'.
  • Wiping out measles, mumps and rubella can only happen if everyone is protected from being infected. If enough people (95% of the population) are vaccinated, the infections will not be able to spread. It only takes a small number of people in the community with an infection to increase the risk of a measles, mumps or rubella epidemic.
  • This also applies to all other infectious diseases. Polio and smallpox are examples of how a disease can be wiped out by making sure that most people are vaccinated in childhood.

The risk of not vaccinating your child against these infections far outweighs any of the known side effects, which have been studied over decades.

For more detailed information, read the National Centre for Immunisation Research and Surveillance fact sheet on the MMR vaccine and autism and the MMR vaccine decision aid.

  1. National Centre for Immunisation Research and Surveillance. MMR vaccine, inflammatory bowel disease and autism. Fact sheet.
  2. Demicheli V, Jefferson T, Rivetti A, Price D. Vaccines for measles, mumps and rubella in children. Cochrane Database Syst Rev 2005;(4):CD004407.
  3. Murch SH, Anthony A, Casson DH, et al. Retraction of an interpretation. Lancet 2004;363:750.
  4. A statement by the editors of The Lancet. Lancet 2004;363:820–1.