The pseudoscience community has long tried to convince parents that the MMR vaccine (to prevent infection with the diseases measles, mumps, and rubella) causes autism, despite study after study after study after study after study after study after study after study* showing that there is no connection between MMR and autism.
The pseudoscience community’s desperate investment in this myth–and the shaky ground they stand on– is illustrated by how quickly they shift their stories:
“Thimerosol or aluminum, or some kind of ‘toxin’ is the cause!” Debunked .
“No, I mean, it’s just too many too soon!” Debunked
“No, but seriously, natural infection is way better because unvaccinated children are healthier than vaccinated children!” Debunked.
And just yesterday, another study (Jain et al. 2015 Autism occurrence by MMR vaccination status among US children with older siblings with and without autism) has come out debunking yet another antivaccine myth: that the MMR vaccine somehow “triggers” autism in children who are genetically susceptible to it.
Some commenters on my blog have expressed various forms of this idea:
“I’m not saying that vaccines are the cause of autism but I do feel that they can be “the straw that breaks the camel’s back” for some individuals who are genetically more suseptable.”
“And to the poster who mentioned that children could have something in them that predisposes them to develop Autism after the shot, I wholeheartedly agree with that. Same as someone who smokes and doesn’t develop lung cancer vs. the other smoker who does develop lung cancer.”
Large genomewide scans of families with a history of autism have shown that there is a strong heritable component to autism, with many different associated genes. (The genetic and developmental mechanisms are still being investigated and are likely quite complicated). So does having one child who develops autism mean that other children in the family are at higher risk of developing autism, if vaccinated with MMR? This study (with a total sample size of 95,727 children) explicitly examined that question by comparing (retrospectively) children with different vaccination statuses with older siblings with or without autism spectrum disorder (ASD). They report:
“In this large sample of privately insured children with older siblings, receipt of the MMR vaccine was not associated with increased risk of ASD, regardless of whether older siblings had ASD. These findings indicate no harmful association between MMR vaccine receipt and ASD even among children already at higher risk for ASD.”
This finding is particularly important for parents who already have a child with autism, who are told again and again by the pseudoscience community that their decision to vaccinate their child is what caused the onset of autism. Barraged by this constant message that autism in one of their children must be due to the vaccine (and the implication that it is their fault!), parents desperate to do whatever they perceive is best for their children may delay or withhold vaccination for subsequent children.
This study should set those parents’ fears to rest.
“Although the study’s findings might have been expected by those in the field and anyone who has followed the research, the research still cost money, and those funds, which came from the National Institutes of Health and a handful of major universities, might have gone to any number of other projects.”
Even with this latest study, I predict that the small (but vocal) anti-vaccine community will find yet another mythical reason why MMR must cause autism. They are desperate to create the illusion that there is a legitimate scientific debate about the safety of vaccines. In many cases they have a huge financial incentive to do so. Read Colin’s account of his visit to an antivaccine conference, where the organizers hawked natural ‘remedies’ and ‘cures’ for autism. A quick search of any of the leaders of the antivaccine movement, such as Bob Sears, Tim O’Shea and “Thinking Moms” reveals that they all have books to sell, speakers’ fees to collect at conferences, and advertising to sell on their blogs. To stay relevant, they have to create fear and uncertainty among parents trying to make the best decisions for their children.
Fortunately, the vast majority of parents understand that vaccination is the best way of protecting their children from infectious diseases, and the voices of the pseudoscientific community are increasingly drowned out by the sheer volume of evidence against them.
*This is a tiny sampling of the research out there–I just did a quick search on PubMed and posted links until I got tired of illustrating this. If you would like to read the papers but can’t access them because of paywalls, get in touch with me.