The Facts about MMR Vaccine and Autism


Measles, Mumps and Rubella – The MMR Vaccine

The MMR is an intramuscular vaccine injected either into the upper arm or thigh. The MMR vaccine is composed of a weakened version of live measles, mumps and rubella viruses. As the viruses are weakened, a person that has just had the vaccine cannot infect other people. The MMR is normally given to children for the first time soon after their first birthday, as by this age the natural immunity that mothers pass on to their children will have faded. A booster jab is also given to children aged three to five.

The MMR vaccine is highly effective against measles, mumps and rubella and has almost wiped out these diseases since it has been introduced in 1988. It has also been used in the United States for 15 years prior to the UK. Worldwide it has been given in over 100 countries.

Is there a link between MMR and autism?

Current studies show no link between MMR and autism.

The assumption that MMR leads to autism started in 1998 after a group of scientists published a paper on 12 autistic children with bowel problems. Although this research did not prove there was a link between the two, the forecoming media interest gave the impression that MMR was connected to autism.


Because the number of children diagnosed with autism has been increasing for many years, some people related this to the MMR vaccine.

Also the symptoms of regressive autism tend to develop in children at around the same time that the first dose of MMR vaccine is given. If MMR caused regressive autism, it would be more common in vaccinated children than in unvaccinated ones. But this is not the case. Also, there would be an increase in cases of autism when the vaccine was introduced in Britain, but there was no increase. Also if the MMR vaccine was withdrawn we would expect a drop in the cases of autism, but it did not happen in Japan when they swapped the MMR for single vaccines.

Many following researches were carried out in Denmark, Sweden, Finland, USA and UK and no links between MMR and autism have been found. The world Health Organization and other experts agree that there is no connection between MMR and autism.

What might be the cause of autism?

There may be a range of causes for autistic spectrum disorder, the main evidence to date suggests that autism is a genetic condition. At the moment researches are still in progress to find out more about the real causes of autism.

Can my child have single vaccines?

MMR is considered the safest option to protect children against measles, mumps and rubella, as due to the time gaps between the three vaccines children could risk catching the diseases which they had not yet been protected against and pass them on to other children and pregnant women.

The World Health Organization does not recommend the single vaccines as they would leave children unprotected for a longer period of time, as they require six injections (initial dose and second dose) with gaps in between, offering no real benefits.


How about overloading my child’s immune system with three viruses all at once?

Children’s immune systems are well adapted to cope with thousands of viruses and bacteria from birth. A baby could respond well to around 10,000 vaccines at any one time. So the baby’s immune system can cope easily with the MMR vaccine.

What are the side effects of the MMR vaccine?

Possible side effects can include the following:

  • Fever between 6 to 10 days after the immunisation (affecting one in ten children). Some children develop measles-like rash and go off their food.
  • The fever may cause fit in about 1 in every 1,000 children who have been immunised. This is called a ‘febrile convulsion’. But the risk of having a fit is 5 times higher in children that have not been immunised and get measles.
  • Three weeks after immunisation some children may develop mumps-like symptoms, including fever and swollen glands, but this is rare.
  • Six weeks after immunisation some children can develop a rash of small bruise-like spots, but this is very rare. This is usually caused by the measles and rubella parts of the vaccine. If this occurs take your child to the doctor who will advise you on what to do in this circumstance.
  • Less than one child in a million develops encephalitis (infection of the brain) after having the MMR. But, if a child catches measles the chances of developing encephalitis is between one in 200 to one in 5000 depending on age.

In case of the child developing a temperature of 39°C or above; or has a fit speak to your doctor immediately. If this is not possible go to your nearest hospital’s emergency department.

If you need any further information about the MMR vaccine speak to your doctor, health visitor or practice nurse.


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