At least a dozen major studies have found that early childhood vaccines do not cause autism. But one possibility remained: that immunizations could cause autism in a small group of children who were already primed to develop the disorder.
Now, new research has ruled out that possibility too.
A study of nearly 100,000 children found that toddlers known to have an elevated risk of autism were no more likely to be diagnosed with the disorder if they were vaccinated against measles, mumps and rubella than if they weren’t. What’s more, the diagnosis rate for high-risk children who were vaccinated was the same as for immunized children with no family history of the disorder, according to the report published Tuesday in the Journal of the American Medical Assn.
By hunting for — and failing to find — a link between the MMR vaccine and autism spectrum disorders, or ASD, in children with an older sibling who had the disease, the study leaves no doubt that the two are not connected, experts said.
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