WATCH: There was already a mountain of evidence the measles-mumps-rubella (MMR) vaccine was not linked to autism, but a major new study has concluded there is no possibility the vaccine is responsible for the condition. Robin Gill reports.
TORONTO – While North America saw a resurgence of the measles again this winter, new research is reiterating yet again that there is no link between the MMR vaccine and autism.
This time around, American researchers say the measles, mumps, rubella vaccine doesn’t increase risk of autism, even in kids who are already at a higher risk of the disorder.
“Consistent with studies in other populations, we observed no association between MMR vaccination and increased autism spectrum disorder (ASD) risk…,” the authors said in a statement.
“We also found no evidence that receipt of either one or two doses of MMR vaccination was associated with an increased risk of ASD among children who had older siblings with ASD,” the researchers say.
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The researchers, out of the Lewin Group – a U.S. health care consulting organization – studied about 95,000 children, some who had siblings with autism.
Studies have already pointed to a correlation between younger siblings being at a higher genetic risk of autism if they have siblings with the neurological disorder compared to the general population. The researchers say an older sibling’s autism diagnosis was sometimes enough to scare parents out of vaccinating their younger children.
Of the 95,727 kids in the study, 1,929 had an older sibling with autism. Another 994 kids in the study group were diagnosed with autism, and only 134 of the new diagnoses came from kids with an older sibling with autism.
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The majority – 860 – came from kids with unaffected siblings. Vaccination dosage didn’t tamper with results either.
Dr. Thomas Frazier II, a Cleveland Clinic Children’s Hospital doctor, said the findings are incredibly relevant.
“It’s an important addition to literature because we’ve known for a while through a large number of studies and samples that MMR is very unlikely to lead to autism. Now we know that it’s not just in the general population, it’s true for high-risk families, too,” he said.
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The scientists hope their findings reassure parents who are hesitant about vaccinating their kids.
“Autism is a highly genetic disorder. At this point, researchers should focus on identifying the genetic causes and how those genes interact with environmental changes,” Frazier said.
Last summer, a scientific review suggested that while childhood vaccines may lead to some side effects, autism and food allergies aren’t concerns despite what a growing anti-vaccination movement may allege.
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“We found evidence that some vaccines are associated with serious adverse events; however, these events are extremely rare and must be weighed against the protective benefits that vaccines provide,” the study authors wrote.
The review was based on 67 papers hand-picked by the scientists based on their study controls, comparison groups and relevance to their analysis. The team narrowed down its research from 20,000 recent papers.
The researchers said that worried parents have refused vaccines for their kids, causing disease to spread through communities. Their hope was to get to the root of the concerns to see if they held any merit.
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Turns out, the measles, mumps and rubella vaccine — dubbed MMR — may lead to fever and seizures, findings that Canadian researchers suggested earlier this year.
But there was “strong evidence” that autism and the vaccine aren’t linked, contrary to what celebrity moms have told the public.
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The research also called vaccines “one of the greatest public health achievements of the 20th century for their role in eradicating smallpox and controlling polio, measles, rubella, and other infectious diseases in the United States.”
carmen.chai@globalnews.ca
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