In the past, a small group of doctors and researchers suggested that vaccination with the MMR vaccine might be linked to autism. But there isn't any good evidence of this.
Here is some more information about this vaccine and autism.About the vaccine
MMR stands for measles, mumps, and rubella (German measles). These are infections that can make your child very ill.
Usually, with the MMR vaccine, your child gets one injection when they are about 13 months old and another one when they are between 2 years and 4 years old.
The MMR vaccine protects your child from all three infections.Why the worry?
A small study in 1998 raised questions about the MMR vaccine and autism.  The researchers thought there might be a link between having the vaccine and getting a problem with your bowels. They thought this bowel problem might cause a kind of autistic spectrum disorder. But in the end, the study's conclusions were that there was no proof of such a link.
The study has now been discredited and withdrawn by the medical journal that published it. 
This study was small, looking at only 12 children. And other researchers said it wasn't done well.  But the study showed up in newspapers and on television. Then many parents decided not to give their children the MMR vaccine. What does the evidence say?
It can be hard to prove beyond any doubt that a vaccine is safe. This is because millions of children get vaccines. And some of these children later get diseases. But this doesn't mean the vaccine caused the diseases.
To prove a link between the MMR vaccine and autism, we would need to do a type of study called a randomised controlled trial. In this study, some children would get the vaccine and some wouldn't.
But this study would be hard to do, for several reasons. We know that vaccines help a lot in stopping infections. So it wouldn't be fair to keep some children from getting vaccines. Also, the study would have to go on for many years, to spot any problems that take time to show up.
Other types of study can give us reliable evidence about the MMR vaccine and autism. Two important types are called cohort studies and case control studies.
In a cohort study, researchers look at a large group of people, usually many thousands, to see how many get autism. Then they check how many of these people got the MMR vaccine.
In a case control study, researchers look at two groups. One group has autism. The other group doesn't. Otherwise, the two groups are very similar. The researchers then check which people had the MMR vaccine.