I see this posted multiple times, & since it references peer-reviewed papers (inconveniently without links), it merits investigation. I’ll read every paper listed, where publicly available, look for further work responding to it or related to it, & comment on its relevance to the original claim.
There’s a lot of material to go through, so I make no commitment about when I’ll finish. This page will be updated as I make progress.
A first description of autism cases by a medical community just discovering this condition.
This has many citations (Google Scholar counts 8389 at the time of writing). This is understandably so – it describes a troubling condition. The fact that this is the oldest study cited also tends to contribute to its citation count.
With regard to the topic, there is little mention of vaccination, & one of the subjects of the study (Paul) suffered from vaccine-preventable illnesses.
There is a mention, in the case of Richard, of having symptoms after a smallpox vaccination at 12 months. It should be noted the inoculation was after the onset of autistic behaviours, not before.
Now, let’s start on the claims enumerated by the article.
Boys who received hepatitis B vaccinations of a type discontinued in 2002 in the first month of life had an increased likelihood of autism by up to 3x.
In total, 86996 boys’ histories were considered in a cross-sectional study spanning birth years 1997 to 2002 that compared those vaccinated against Hepatitis-B in the first month of life against those never vaccinated against it, & attempted to adjust for confounding factors.
A significant result was found – that boys born before 1999 with a vaccination record, who received the first dose of hepatitis B vaccine during the first month of life were 3.002 times more likely to receive an autism diagnosis than those vaccinated later or not at all. This is what is mentioned in the paper’s abstract.
The 95% confidence interval for this result is 1.109 to 8.126. That is, the authors are 95% confident that the true value is between 1.109 and 8.126, and believe the most likely value is 3.002.
There’s a fair discussion of the findings provided by the authors, and suggestions for more research into vaccination scheduling. Since the background to the the original claim is that vaccines are harmful, it is relevant to print the last sentence here:
Our findings do not suggest that the risks of autism outweigh the benefits of vaccination; however, future research into hepatitis B vaccination scheduling is warranted.
While an interesting study on the effects of heavy metal poisoning, this paper neither mentions, nor is relevant to, vaccination.
It could be imagined that the relevance to vaccination is that Thimerosal or Thiomersal (a preservative used until recently in many vaccines, now less popular due to unfounded public mistrust) is a chemical that has a mercury atom.
Mercury is a toxic heavy metal, so would certainly qualify as an environmental toxin. The dangers of heavy metals are usually due to the body’s poor ability to rid itself of them, & so a slow build-up to a dangerous dose occurs.
Fortunately, chemistry can produce profound changes in the behaviours of atoms when they are combined in molecules. For example, while chlorine is a dangerous greenish gas that was used to devastating effect to kill soldiers in the first World War, attaching a sodium atom to it produces sodium chloride (AKA table salt).
In the same way, despite the fact that mercury is a dangerous poison, capable of slowly building up in the body (it reduces by half in about 120 days), Thiomersal, while also toxic, decomposes into ethylmercury readily in the blood. The body can get rid of half all its ethylmercury in roughly 18 days – almost 10 times faster than inorganic mercury. This is still dangerously cumulative, but much less so that inorganic (neat) mercury.
There has been no link yet found between Thiomersal and autism spectrum disorder (ASD).
The main source of mercury for people is dietary. Vaccines are not the source of heavy metal poisoning you’re looking for.
A large quantity of literature was reviewed. Multiple causes for autism have been identified, & are suspected to overlap. The association of vaccines to autism was limited to implication & hypothesis.
I.e. there might be a link between vaccinations & autism, but we don’t know if there is one.
There is an autism epidemic. A great deal of work is being done to understand the epidemic, & this document provides a summary up to 2011. Included, is also a substantial description of the effects of ASDs & other similar effects, such as heavy metal poisoning.
Much content of this review was devoted to the work on vaccinations. It makes mention of the coincidence of changes to vaccine regimes & increases in autism prevalence. Other than temporal association, the only other potential link between vaccinations & autism is the fact that Thiomersal contains mercury, & the effects of mercury poisoning include the chief symptoms of autism.
Dendritic cells are sensitive to Thiomersal. One cited article references autism in its title. No further references to autism. While it’s possible dentritic cells are involved in autism, nobody knows how autism works.
The only link I can imagine the author of the original claim might make from autism to this paper is that autism is suspected to be linked to immune system abnormalities, & dendritic cells are a part of the immune system.
It could be the case that Thiomersal contributes to autism. Still no evidence, just more calls for more research, which is being done.