Do Vaccines Cause Autism? The Origins Of The Myth

It’s been almost 70 years since the ‘refrigerator mother’ surfaced as an explanation of autism. The hypothesis, since debunked, was courtesy of Leo Kanner and Bruno Bettelheim, both physicians with the taste for the fad of the day – psychoanalysis. More wild suggestions as to what causes autism have followed.

Because the cause of Autism Spectrum Disorder (ASD) has not been clearly pointed out yet even though the most recent and largely backed up hypothesis has to do with genetics, for decades it was easy to speculate about what causes autism. In some parts of the world more ‘traditionalist’ psychoanalysts still blame mothers of autistic children for being ‘too cold’ and career-oriented, whether such claims are objectively true or not.

But by far our ‘favorite’ debunked hypothesis about what causes ASD is the ‘vaccines cause autism’ one. FindMeCure has always been on the side of science, so this World Autism Awareness Day we’d like to take a look at the origins of the myth, the validity of the claim and how perpetuating it affects children now.

We believe that unscientific claims about the cause of autism prey on the need of parents to have an outlet for their fear and anxiety. But just like the ‘refrigerator mother’ puts a huge burden of blame on their shoulders, the ‘vaccines cause autism’ myth shames parents for wanting to prevent long-forgotten diseases that can cause real damage.

We’re on the side of science here and we’re also on the side of parents – we understand the instinct to protect your children and make the best decision for their health. Let’s see where the claim that vaccines cause autism comes from, so you can have all the information you need to make the right call.

The ‘vaccines cause autism’ myth began in the late 90s (‘97 according to some sources, ‘98 according to others) with a paper by Andrew Wakefield who had previously worked on a theory that the measles virus was causing colonic lesions in people with Crohn’s disease – a theory later debunked. In this paper Wakefield went after the measles, mumps, and rubella vaccine (MMR vaccine), claiming it causes lesions and inflammation in the digestive tract that then enter the bloodstream and go to the brain. His only subjects – 12 children with developmental difficulties, of which 8 had autism.

Though Wakefield’s bold claim was that intestinal inflammation caused by the measles virus lead to autism, signs of inflammation were first observed after the children had been diagnosed with autism, not before that, so autism symptoms preceded any intestinal damage.

What’s more, for such a hypothesis to hold water, a study should be conducted with both children with and without autism to see if there is any causal link between vaccines and the developmental condition. Wakefield’s study was done only in children with developmental delay with no comparison group, which already raises questions about scientific integrity and research misconduct. Remember when we talked about the ‘gold standard’ of clinical research? Well, a lot of the objections against Wakefield’s study have to do with the study design itself which leads to biased results and does not take into account the best practices like blinding and control groups.

Since Wakefield’s claims were published, however, a number of studies began investigating the correlation between MMR vaccines and autism. But even as parents were opting out of vaccinating their children, the rate of autism diagnoses didn’t decrease, quite the opposite. One hypothesis for the increasing rates of autism actually suggests that more children are being diagnosed not because more children have autism, but because criteria become more precise and professionals become better at picking up the clues earlier even in children with what is known as ‘high-functioning’ autism who were previously harder to diagnose.  

However, another concern about the MMR vaccine was soon to be debunked. If not the measles virus in the vaccine, then some other component surely had to be the cause of autism. The antiseptic thimerosal used to prevent contamination of the vials was the next suspect.

Because thimerosal contains mercury (though in safe, controlled doses) it quickly became the bad guy, with mercury being linked to central nervous system (CNS) damage. Although research shows no link between the small, controlled amount of mercury in the vaccine and autism, between 1999 and 2001 thimerosal was removed from childhood vaccines and now even the flu shot has a thimerosal-free alternative.

Regardless of the fact that nine different studies deny a link between the MMR vaccine and autism, the myth persists among concerned parents who just want to make the best possible decision for their children’s health. Doing harm by inaction can seem better than doing harm by taking the wrong action, especially when preventing a long-forgotten disease appears so abstract. In rare cases measles, for example, can cause encephalitis (inflammation of the brain) and blindness but chances are, you don’t personally know anyone who’s had this experience and so the thread doesn’t seem as real.

Even though we know that some childhood diseases can have severe complications (polio can cause paralysis, mumps can lead to meningitis, they seem so rare compared to autism that parents may decide to take a risk and count on their child’s strong immune system. However, for people with compromised immunity who rely on herd immunity to stay safe, such ‘rare complications’ can very real. Vaccinating children not only prevents them from contracting at best an unpleasant infection that requires bed rest but it also protects other children who can’t get vaccinated from the risks of the worst case scenario, which for people with compromised immunity is much more probable.

But let’s go back to what causes autism. Parents usually spot the first signs of autism when their child is around 18 months old, which is typically a few months after their first childhood vaccinations. Proximity in time, however, doesn’t equal causation. In fact, recent research suggests the first signs of autism usually precede vaccination.

A strong indication that autism may be genetic is research on identical and fraternal twins which shows that 92% of identical twins and 10% of fraternal have ASD. Another study that used ‘home-movies’ family videos suggests that a trained professional can spot subtle signs of autism as early as infancy, preceding the MMR vaccine. What’s more, there is some evidence to support the hypothesis that autism first begins during pregnancy, in the first 24 gestation days to be precise.

That being said, knowing when autism starts is not the same as knowing what causes it, it just shows that fists signs can be observed before the child has been vaccinated for MMR. As with many other disorders, researchers are still looking into possible factors trying to find the cause of autism.

One thing is clear, however – parents are not to blame for their child developing autism. We know how disheartening it can be to find out that the medical world doesn’t have the answers either. But even though medical research hasn’t found the cause of autism yet, enough studies show that vaccines are not it. Whatever developmental difficulties a child may experience, their health, as well as the health of immunocompromised children and adults, depends on parents trusting medical professionals.