RFK Jr Claims We Will “Know” The Cause Of Autism By September. Science Says That’s Very Unlikely

There’s no scientific evidence whatsoever to suggest a link between childhood vaccinations and the development of autism. This has been demonstrated time and time again in large, robust studies. Nevertheless, a survey in 2024 found that a quarter of US respondents continued to hold the belief that the MMR (measles, mumps, and rubella) vaccine is linked to autism.

Much like infectious diseases themselves, this myth is proving astonishingly difficult to eradicate.

The news that HHS was planning yet another study into this comprehensively refuted theory was therefore met with consternation from many scientists, who also called into question the alleged decision to appoint David Geier – described as “long-discredited” and a “vaccine skeptic” by The Washington Post – to head it up.

Now, in a cabinet meeting on Thursday, April 10, Kennedy reportedly claimed, “By September we will know what has caused the autism epidemic. And we’ll be able to eliminate those exposures.” On a purely scientific level, there are a number of problems with this statement.

Are autism rates increasing?

Firstly, the very characterization of autism as an “epidemic” is controversial. That language may tend to evoke the idea of “disease”, which autism is not.  

It is true that autism diagnosis rates have increased in recent years – a 2023 report from the Centers for Disease Control and Prevention (CDC) found that one in 36 US 8-year-olds are likely to be autistic, up from a previous estimate of one in 44.

Experts are divided on the question of whether more diagnoses mean there truly are more autistic people now than at other times in our history, or whether it indicates an issue of overdiagnosis.

In countries such as the US and UK, awareness of autism and neurodiversity in general has improved over the last couple of decades. This is a good thing if it leads to greater acceptance of autistic people in society, or allows people who may have missed out on support as children to seek a diagnosis that brings them self-acceptance and access to accommodations later in life.

With greater awareness and more people seeking autism assessments, however, comes the question of whether people are receiving diagnoses where in years past they may not have met the clinical threshold.

This is augmented by the fact that the clinical guidelines used to diagnose autism have evolved over the years. One example of this is the removal of “Asperger syndrome” as an official diagnosis. While newly diagnosed people will not be given this label any longer, there are those who choose to continue to identify with it.  

Dr Conor Davidson, Autism Champion at the UK’s Royal College of Psychiatrists, discussed the possible ramifications of overdiagnosis in a blog post. One consequence could be that people with certain mental health conditions are misdiagnosed as autistic and thus don’t receive specific treatments that could benefit them.

Others have raised concerns about unreliable information being dished out on social media, which may lead people to incorrectly diagnose themselves with autism. However, any discussion around that topic must also include an appreciation of the often long waiting times for official assessments, which can lead people to seek out other sources of information out of desperation.

Taken at face value, increasing rates of autism diagnoses may be seen as a negative or concerning thing; however, the numbers alone don’t reflect the experiences of autistic people, the fact that many consider getting their diagnosis a positive step, and the various complex reasons why these numbers are increasing.

And what is more, many autistic people have argued that seeking to somehow “eliminate” autism is inherently offensive. Rather than something to be feared, they say, autism and other neurodivergent conditions should instead be accepted and celebrated.

“[If] everybody is different, [then] that must be because the sum is greater than the parts, that diversity of human neurocognitive capability is integral to the survival of the species and our evolution,” Dr Tony Lloyd, CEO of the ADHD Foundation, told IFLScience.

What could RFK Jr mean by “exposures”?

Just as lots of research time and effort has gone into disproving the notion of a link between autism and vaccines, many experts have been conducting studies to try to figure out what does cause autism.

We don’t have a definitive answer yet, and we may never do. Autism is complex and heterogeneous, and is likely caused by a mixture of factors.

One promising avenue has been genetic research. A recent study found that rare DNA sequences passed down from our Neanderthal ancestors occur at higher rates in autistic people, on average, than non-autistic people. So far, it’s unclear exactly how these gene variants could be playing a role in autism, if indeed that is the case.

Continuing the theme of ancient genetic material, some research has suggested that endogenous retroviruses could be involved. Virus-derived sequences from ancient retroviruses, the ancestors of modern viruses like HIV, became embedded into the genomes of our human antecedents and were passed down through the generations. These “fossils” are now thought to make up about 8 percent of the human genome and their impact is still not fully understood.

A study published in 2020 identified 102 genes associated with the development of autism, using more than 35,000 genetic samples. Some mutations that increase the chances of someone being autistic may be inherited, and some may arise spontaneously. Again, it just highlights the complexity of the issue at hand.

As Joseph Buxbaum, Director of the Seaver Autism Center, told IFLScience at the time, “[P]atient-based research is complicated now because the easy stuff has been figured out.”

According to the National Institute of Environmental Health Sciences (NIEHS), growing attention is being paid to the possible environmental factors that could also be involved. These include exposure to certain pesticides and air pollution.

“But these factors alone are unlikely to cause autism,” says NIEHS. “Rather, they appear to increase a child’s likelihood for developing autism when combined with genetic factors.”

All of the scientific evidence to date, therefore, flies in the face of claims – made largely by antivaxxers – that some single ingredient or compound is causative of autism.

President Trump recently made comments that fan the flames of this kind of speculation. As reported by CNN, among others, the President said, “If you can come up with that answer where you stop taking something, you stop eating something or maybe it’s a shot, but something’s causing it.”

Hoping for a simple answer to a complex scientific question is one thing; entering into an investigation with the expectation you will definitely find one – and by a set date – is quite another.

How scientific investigations are supposed to work

A scientific investigation begins with what we call a “null hypothesis”. This is a statement capturing the idea that there is no difference between the conditions or populations being studied.

In a study seeking to find out whether the MMR vaccine causes autism, the null hypothesis would be something like, “Rates of autism are no higher in people who have received the MMR vaccine.”

The aim of your investigation, therefore, is to run experiments that will allow you to test this hypothesis and gather data. Only if you have enough data that points in the opposite direction do you reject the null hypothesis, and scientists and statisticians have established benchmarks that must be reached before this can be the case.

All this to say, unless you do reach those benchmarks, you cannot assume the null hypothesis is not true. When scientists find new, exciting results, what they’re actually celebrating is their baseline assumption being proved wrong.

What science should not be about is going in with a preconceived idea and searching only for data that proves you right.

Hopefully, this illustrates why it is scientifically suspect when someone makes a statement like “we will know what has caused the autism epidemic” before an investigation has actually finished.

It’s also worth saying that this whole process doesn’t really work to a strict deadline. Scientists plan their investigations carefully – indeed, they usually have to as part of the process of securing funding for their research. But even the best-laid plans can be derailed.

As those involved in life and health sciences research know only too well, living systems can often throw some curve balls into the mix. If the process of doing science is about discovery, it’s kind of baked-in that you might come across something unexpected. And that’s why such a bold statement as the results of a study being definite “by September” is questionable.