Autism is a life-changing diagnosis for both parents and children, and the search continues for the exact cause — but you won’t find it in a needle. Another major study, published in the Journal of the American Medical Association, has reinforced the conclusion that there is no link between autism and the MMR (measles, mumps, and rubella) vaccinations.

"Consistent with studies in other populations, we observed no association between MMR vaccination and increased ASD risk among privately insured children," the authors wrote. "We also found no evidence that receipt of either 1 or 2 doses of MMR vaccination was associated with an increased risk of ASD among children who had older siblings with ASD."

Researchers studied more than 95,000 children along with their older siblings in order to show their MMR vaccine had no causal relationship between the 1,929 older siblings in the group that were diagnosed with autism spectrum disorder (ASD). When a child had an older sibling with autism, it put them into a high-risk category for developing it themselves because of the genetic prevalence researchers previously identified.

By the time a child turned 2 years old, 73 percent of their peers in the study were vaccinated, and by the time they were 5 years old, a total of 86 percent were vaccinated. At least 84 percent of the children who had MMR vaccinations did not have autism and neither did their siblings. Researchers reached a consensus when they found children with older siblings who were diagnosed with autism and also vaccinated at high rates didn’t develop any form of ASD.

Why would there be a misconception about vaccines linking to autism? It all started in 1998, when British surgeon and medical researcher Dr. Andrew Wakefield published a study that made the false connection. The study was later retracted because of its inaccuracies and Wakefield was stripped of his medical license, but once the lie had been let loose it became nearly impossible to contain.

Today, one in four parents still believes there is a link between vaccines and ASD, a brain development disorder, which causes social, cognitive, and communication impairments in one out of every 68 children, according to Autism Speaks. Despite over 15 years of studies disproving the causal link between the two, there are still people who follow the belief, according to researchers.

Researchers added, "As the prevalence of diagnosed ASD increases, so does the number of children who have siblings diagnosed with ASD, a group of children who are particularly important as they were under-vaccinated in our observations as well as in previous reports."

Source: Jain A, Newschaffer CJ, Marshall J, Buikema A, Bancroft T, and Kelly JP. Autism Occurrence by MMR Vaccine Status Among US Children With Older Siblings With and Without Autism. JAMA. 2015.