There is no link between the MMR jab and autism, according to the authors of a new study published in the Archives of Disease in Childhood.
Back in 1998, research on 12 children published in the medical journal The Lancet, suggested there was a link between the vaccine, autism and bowel disease, which led to a drop in the number of children having the jab for mumps, measles and rubella.
The latest research, which is the largest ever published study on the issue, looked at a sample of almost 250 children aged between 10 and 12, who were born between July 1990 and December 1991 in the South Thames area of England.
It followed 98 children who had an autism spectrum disorder (ASD) and two comparison groups: 52 children with special educational needs but no evidence of autism spectrum disorder, and 90 children who were normal.
All the children had been vaccinated against MMR, but not all of them had been given both the doses needed for maximum immunity.
Blood samples were taken from all the children to check for the presence of persistent measles infection or an abnormal immune response.
This was indicated by a circulating measles virus or increased antibody levels.
And the researchers found there was no difference in virus or antibody levels between children with ASD and the comparison groups.
They concluded: "No difference was detected in the distribution of measles antibody or in measles virus in ASD cases and controls whether the children had received the first, second or both MMR vaccinations."