What Causes Autism?

This infographic presents some of what we know about immune activation events causing autism and states the vaccine-autism hypothesis.

Given the close association between the immune system activations and autism, supported by animal testing, the vaccine-autism hypothesis is highly plausible.

After all, the purpose of vaccines is to activate the immune system, which is something we know can trigger autism.

Sources are listed and linked below, and I have copied a line from the abstract of each study for the convenience of the reader.


  1. Hallmeyer, 2015: Autism heritability was estimated to be 38% and the shared environmental component to be 58% https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4440679/
  2. Atladottir, 2010: admission to hospital due to maternal viral infection in the first trimester and maternal bacterial infection in the second trimester were found to be associated with diagnosis of ASDs in the offspring https://www.ncbi.nlm.nih.gov/pubmed/20414802
  3. Zerbo, 2015: women with infections diagnosed during a hospital admission, particularly bacterial infections, were at increased risk of delivering a child with ASD https://europepmc.org/articles/pmc4108569
  4. Vargas, 2005: The brains of people with ASD show a marked activation of microglia and astroglia, and cytokine profiling indicated that MCP-1 and TGF- β1, derived from neuroglia, were the most prevalent cytokines. Cerebrospinal fluid showed a unique proinflammatory profile of cytokines, including a marked increase in MCP-1. https://www.ncbi.nlm.nih.gov/pubmed/15546155
  5. Li, 2015: Neonatal vaccination of rats with bacillus Calmette-Guérin and hepatitis B vaccines modulates hippocampal synaptic plasticity https://www.ncbi.nlm.nih.gov/pubmed/26531688
  6. Wei, 2011: The cerebellum of the brains of people with ASD has increased IL-6, which alters neural cell adhesion, migration and synaptic formation https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3114764/
  7. Abdallah, 2013: The amniotic fluid of mothers of children with ASD showed elevated levels of inflammatory cytokines https://www.ncbi.nlm.nih.gov/pubmed/22175527
  8. Suzuki, 2013: In multiple brain regions in people with ASD there is excessive microglial activation https://www.ncbi.nlm.nih.gov/pubmed/23404112
  9. Jones, 2017: The serum of mothers of children with ASD with ID showed increased levels of maternal cytokines and chemokines during gestation https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5122473/
  10. Tsilioni, 2019: The brains of children with ASD have increase inflammatory cytokines https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6027314/
  11. Smith, 2007: Maternal immune activation (MIA) in mice alters fetal brain development through interleukin-6 https://www.ncbi.nlm.nih.gov/pubmed/17913903
  12. Malkova, 2012: MIA in mice results in offspring that show more autism-like behaviours https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3322300/
  13. Bauman, 2014: MIA in rhesus monkeys yields offspring with abnormal repetitive behaviors, communication, and social interactionshttps://www.ncbi.nlm.nih.gov/pubmed/24011823
  14. Choi, 2016: Either MIA or direct administration to the fetal brain of mice of inflammatory cytokine IL-17a promotes abnormal cortical development and ASD-like behaviors in offspring https://www.ncbi.nlm.nih.gov/pubmed/26822608
  15. Missig, 2018: Early-life immune activation in mice can lead to long-lasting physiologic perturbations that resemble medical comorbidities often seen in ASD and other neuropsychiatric conditions https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5770773/

MMR-Autism Association in DeStefano 2004 Study

William Thompson is the CDC whistleblower who revealed that he had been involved in a cover-up of a key result in the vaccine-autism debate.

He was referring to the DeStefano 2004 study of MMR and autism, on which Thompson was a co-author, conducting the statistical analysis. Thompson claimed that an association between MMR and autism in African American boys was identified in the data, but that the finding was omitted from the final paper. He cited the pressure to show no association between MMR and autism, and explained how they tried various statistical techniques to try to hide the association.

The infographic above presents the data behind the debate. Brian Hooker’s 2014 re-analysis of the data shows there is indeed an association between MMR and autism in African American boys in the data.

Forget the politics; the science here is telling us there is an association between a vaccine and autism.


Vaccine Autism Studies Inadequate

In 2012, the Institute of Medicine (IOM) released a comprehensive evidence review entitled “Adverse Effects of Vaccines: Evidence and Causality”.

They looked at 8 different vaccines and 76 different adverse events. One of these adverse events was autism.

  • For 1 vaccine (MMR), the IOM favored rejection of a causal relationship.
  • For 1 vaccine (DTaP), the IOM declared the evidence inadequate to accept or reject a causal relationship.
  • For the other 6 vaccines in the review, the IOM did not look for any evidence regarding a causal relationship.

Clearly then, the correct conclusion of this evidence is NOT that “vaccines do not cause autism”. There is not enough evidence to make that conclusion.

Even if a causal relationship between MMR and autism is rejected, it does not follow that “vaccine do not cause autism” because MMR is only one of 8 or more vaccines, and the evidence is inadequate to accept or reject a causal relationship for them. There have also been no studies looking for associations between cumulative vaccinations, or different timings, or different combinations of vaccines, and autism.

The CDC cites this IOM report for its claim that “vaccines do not cause autism” and yet this report does not support this claim.

Maternal Immune Activation and Autism

The diagram in the infographic above comes from:

The CDC Vaccine-Autism Studies

The studies cited by the CDC on their “Vaccine Do Not Cause Autism” page cannot possibly support that claim. The CDC’s conclusion is invalid.

See the infographic above for details about why that is.

The Vaccine-Autism Hypothesis

Here are the sources for each point in the above infographic.

Genetic / Environmental Etiology

The Claim: Autism is partly but not wholly genetic; it can be triggered in genetically susceptible individuals by environmental factors that alter neurodevelopment

The Sources:

Infections in Pregnancy

The Claim: A wide range of bacterial and viral infections during pregnancy are associated with autism, so one trigger is a serious immune activation event during a critical stage of neurodevelopment

The Sources:

  • Atladottir, 2010: admission to hospital due to maternal viral infection in the first trimester and maternal bacterial infection in the second trimester were found to be associated with diagnosis of ASDs in the offspring  https://www.ncbi.nlm.nih.gov/pubmed/20414802
  • Zerbo, 2015: women with infections diagnosed during a hospital admission, particularly bacterial infections, were at increased risk of delivering a child with ASD  https://europepmc.org/articles/pmc4108569

Immune Activations in Animals

The Claim: Immune activations in pregnant or newborn animals alter neurodevelopment and increase autistic-like behaviors in the pups and infants; multiple immune challenges multiply the effect.

The Sources:

Inflammation and Autism

The Claim: Inflammation is an immune system response to a challenge.  Inflammation is associated with autism.

The Sources:

Vaccines and Immune Activation

The Quote: “Immune activation is the objective of vaccines”

… is from Matheson vs. Schmitt, Plotkin Deposition, 16:27:56, 11 Jan 2018  https://www.cafepeyote.com/files/Plotkin_Deposition_-_Summary.pdf or https://youtu.be/DFTsd042M3o?t=24959

Here is the context of the quote:

  • QUESTION: Are you familiar with the study called “Maternal Immune Activation Alters Fetal Brain Development through Interleukin-6” [Smith, 2007]?
  • PLOTKIN: Vaguely, yes. Yeah.
  • QUESTION: Published in the Journal of Neuroscience?
  • PLOTKIN: Yeah, well, I don’t remember the journal.
  • QUESTION: Is that one of the journals you consider respectable?
  • PLOTKIN: Yes.
  • QUESTION: And this was out of the University of California Medical Center. This is from California Institute, CalTech. That institution did a number of studies regarding — that group did a number of studies relating to immune activation and neurological disorder, correct?
  • PLOTKIN: Yes.
  • QUESTION: And they found a connection between immune activation and neurological historical disorders, correct?
  • PLOTKIN: Yes.
  • QUESTION: Okay. And one of the study’s findings they had was that immune activation alters fetal brain development through interleukin-6, correct?
  • PLOTKIN: As I said before, IL-6 is an important cytokine. I would point out in relation to immune activation, that immune activation occurs as a result of disease and exposure to a variety of stimuli, not just vaccines.
  • QUESTION: But it can be caused by vaccines, correct?
  • PLOTKIN: Immune activation is the objective of vaccines.

The Claim: Challenges to the immune system can come from wild pathogens or from vaccines

This is confirmed by the quote above from Plotkin, as well as any immunology textbook.

The Claim: Vaccines must activate the immune system strongly in order to work

The Claim: Aluminum adjuvants are used in many vaccines specifically to increase the challenge to the immune system and boost the response

These two claims are basic to how vaccines work, as explained on the websites of the CDC and the CHOP:

 “An adjuvant is an ingredient used in some vaccines that helps create a stronger immune response in people receiving the vaccine. In other words, adjuvants help vaccines work better. Some vaccines that are made from weakened or killed germs contain naturally occurring adjuvants and help the body produce a strong protective immune response. However, most vaccines developed today include just small components of germs, such as their proteins, rather than the entire virus or bacteria. Adjuvants help the body to produce an immune response strong enough to protect the person from the disease he or she is being vaccinated against. Adjuvanted vaccines can cause more local reactions (such as redness, swelling, and pain at the injection site) and more systemic reactions (such as fever, chills and body aches) than non-adjuvanted vaccines.”

CDC https://www.cdc.gov/vaccinesafety/concerns/adjuvants.html

 “Aluminum is used in vaccines as an adjuvant. An adjuvant is a vaccine component that boosts the immune response to the vaccine. Adjuvants allow for lesser quantities of the vaccine and fewer doses. The adjuvant effects of aluminum were discovered in 1926. Aluminum adjuvants are used in vaccines such as hepatitis A, hepatitis B, diphtheria-tetanus-containing vaccines, Haemophilus influenzae type b, and pneumococcal vaccines, but they are not used in the live, viral vaccines, such as measles, mumps, rubella, varicella and rotavirus.”

CHOP https://www.chop.edu/centers-programs/vaccine-education-center/vaccine-ingredients/aluminum