The largest study so far into vaccines and autism has concluded there is no link, even in children who have a higher risk of developing the disorder. In fact, the researchers found that unvaccinated children were more likely to go on to be diagnosed with autism than those who received vaccines.
The myth that vaccines cause autism has been debunked many, many times.
In 1998 Andrew Wakefield published a study based on 12 children that linked the measles, mumps, and rubella (MMR) vaccine to autism. The results have not been replicated, and it later transpired that he had falsified data, for which his medical license was revoked.
Another study in 2017 linked aluminum in vaccines to autism. This study was withdrawn after scientists noticed images had been manipulated, and one of the co-authors claimed that figures in the paper were deliberately altered before publication.
Nevertheless, the myth persists and can spread around the Internet like wildfire, contributing to a situation where measles cases have doubled in the last year and teenagers are forced to get the vaccine behind their parents' backs.
The latest study to conclude there is no link between the MMR vaccine and autism looked at 657,461 children born in Denmark between 1999 and 2010, including 6,517 children who were diagnosed with autism spectrum disorder (ASD).
The study, published in Annals of Internal Medicine, found that children who had siblings with autism were seven times more likely to go on to be diagnosed with ASD than children without a family history of the disorder, and boys were four times more likely to be diagnosed than girls.
However, even in these higher-risk groups, there was no link between getting vaccinated and being diagnosed with autism.
In fact, the Danish team found that the 5 percent of children in the study who had no vaccinations were 17 percent more likely to be diagnosed with autism than those who had received vaccinations.
"The study strongly supports that MMR vaccination does not increase the risk for autism, does not trigger autism in susceptible children, and is not associated with clustering of autism cases after vaccination," the authors from the Statens Serum Institut in Copenhagen conclude in their paper.
The study adds to the (already very large) body of evidence that shows there is no link between vaccines and autism.
“Parents should not skip the vaccine out of fear for autism,” lead study author Dr Anders Hviid told Reuters. “The dangers of not vaccinating includes a resurgence in measles which we are seeing signs of today in the form of outbreaks."