Vaccines Definitely Don't Cause Autism
There is incredibly strong scientific evidence proving that childhood vaccines are safe
The argument about vaccines and autism isn’t new. If you’ve been on the internet for long enough, and spent even a fraction of your time talking about vaccination, you will have been faced with someone furiously arguing that childhood vaccines are making people autistic. Thing is, we’ve known for decades that this was not true.
Sadly, the recent attention given to RFK Jr. as a presidential candidate in the United States has caused this long-disproven myth to rear its ugly head yet again. I thought it worth going through some of the data that shows that vaccines don’t cause autism, and what the likely reasons for the increase in autism that we see today actually are.
One of the most solid, replicable, and proven findings in the vaccine space is that there is no connection between childhood immunizations and autism.
The Myth
It’s impossible to talk about the vaccine-autism theory without at least mentioning the background. In the late 80s and early 90s, autism was quickly going from a rare condition that impacted a handful of children to something that was increasingly common across society. People started getting very nervous as the number of autistic children skyrocketed.
We know now that almost all of this increase is basically illusory. What actually happened was a fairly simple change in how autism is diagnosed. In the 1950s and 60s, when the condition was first described, it was called childhood or infantile schizophrenia, and only people who were entirely nonverbal and had extreme cognitive issues met the criteria. However, as the decades moved on, the definition of autism was expanded to include a much broader array of individuals. By the 80s, when the Diagnostic and Statistical Manual of Mental Disorders was updated to its third edition, the definition of autism included a much broader array of people. By the early 2000s, this had expanded further with the introduction of Autism Spectrum Disorders.
And this isn’t just conjecture - there’s a huge wealth of evidence showing that most of the increase in autism rates since the 60s is due to changes in how we diagnose the condition. A 2015 study that included every child born in Denmark estimated that 60% of the increase in autism rates in the country could be explained just through changes to the diagnostic criteria and how these were applied to children. Another study which compared a huge cohort of surveyed children and parents to every child born in Sweden from 1992-2004 found that there was no increase in autism symptoms in children during this time, even though the number of kids registered as having an autism diagnosis increased dramatically.
However, all of these studies came quite a while after the early 90s. At the time, there was a terrifying increase in a previously unknown issue, and into this knowledge gap a since-disgraced doctor suggested one cause: childhood immunizations.
The Scandal
In 1998, Andrew Wakefield and colleagues published a study of a handful of autistic children in the prestigious medical journal The Lancet. This paper was retracted by the journal, citing serious breaches of ethics, in 2010. In this study, there was a very vague association between the Measles, Mumps, and Rubella (MMR) immunization and a small pool of 12 autistic children. Specifically, the authors claimed to have found a handful of children in whom the diagnosis of autism was temporally correlated with gastrointestinal issues, which they then attributed to the MMR vaccine.
Nearly three decades later, we know that there was a deeply problematic backstory to this paper. Patients involved in the study claim they were lied to about the methods, aims, and ambitions. The data may in places have been laundered to show a worse picture of vaccines.
I’m not going to go into the details of this entire sordid saga. Brian Deer, an investigative reporter, dug into the issue for over a decade. His book, The Doctor Who Fooled The World, is an excellent read if you’re interested in the horrifying story of how a fraudulent and unscientific paper created huge panic about vaccines which we’re still dealing with today.
However, the response to the publication was immediate. There was a massive media storm questioning whether autism - remember, at the time a pretty new and scary thing - was being caused by the very things we were giving to children to keep them safe. This set off a huge outcry about the vaccine. Scientists across the world quickly started looking into the question of whether autism could be caused by childhood vaccinations.
The Evidence
At last, we get to the evidence. This is where the debate really ends when it comes to vaccines and autism.
There are quite literally dozens of huge, population-wide studies at this point that have looked at whether children who have been vaccinated with the MMR jab have higher rates of autism than those who have not. There is not a single paper that I’m aware of which has found even the suggestion of an increased risk. A relatively recent paper from 2014 found that aggregating together ten separate papers including well over a million children produced an estimated risk of autism that was precisely identical between vaccinated and unvaccinated kids.
Another study using the data from every child born in Denmark between 1992 and 1998 found a non-significantly decreased risk of autism diagnosis in children who got their MMR vaccination. The 2019 update to this paper used data from 1992 all the way to 2010, and found precisely the same results. Even in specifically selected subgroups, such as young boys of a certain age, there was no increased risk of autism conferred by the MMR shot. Another 1998 study from Finland published soon after the Lancet paper found no association between gastrointestinal upset, autism, and the MMR immunization. A 2003 systematic review looked at the evidence available at the time, and found that there was no relationship between MMR vaccination and future autism risk, although they couldn’t fully exclude a potential risk at that point.
I can’t cover all the research that’s been done to prove that vaccines don’t cause autism, because we’re talking about the concerted effort of decades here, but even as a start those papers are quite hard to argue with. Robust, population-wide surveys have not shown even the most minimal risk.
The problem is that the myth of autism and vaccines keeps shifting, as each claim gets disproven in turn. The original idea was that autism was caused by some sort of gastrointestinal issue which itself was related to the MMR. When this was soundly discredited, the claim moved on to be about a small subsection of autism diagnoses, or only about Black children in the US, or about thiomersal, an additive which was removed from most vaccines decades ago, or maybe about the minuscule aluminium doses that some vaccines contain. These arguments have, in turn, been investigated, and none have held up, but that’s not enough to convince the true believers who merely shift to a new and even more implausible explanation for a phenomenon which does not appear to exist.
Vaccines Cause Adults
And really, that’s the bottom line. We don’t need to go into every bizarre theory about how vaccines could potentially maybe increase a child’s risk of autism slightly, because we know, through enormous volumes of hard data, that they don’t. That’s not conjecture. An association that doesn’t exist does not require explanation. Vaccines don’t increase a child’s risk of autism, ergo we do not need to worry about implausible theories speculating that they could.
There’s a great deal of evidence that vaccines don’t cause autism, and we’ve actually identified the reasons behind the increase. As diagnostic criteria were updated over the years, for good reasons including defining who gets medical and social benefits to assist with their lives, more people were captured under the term “autistic'“. This is a very well-understood phenomenon - exactly the same thing has happened with some diseases like hypertension and diabetes.
Every medical intervention comes with some risk, and I’m not going to say that vaccines are always perfectly safe, but the risks and benefits of childhood immunizations are very well understood. Yes, there are some rare but also quite serious adverse events, but on the whole there are few things more beneficial in medical science than the vaccines which have prevented what used to be constant pandemics of childhood infectious diseases. Gone are the days when every two years measles would sweep through our children, leaving death and disability in its path. We have vaccines to thank for that.