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CDC study to find link between vaccines and autism — REVISED

According to news reports, the Centers for Disease Control and Prevention (CDC) is planning a study of potential links between vaccines and autism spectrum disorder (ASD). Despite extensive scientific research that has disproven or failed to find evidence of such links, the CDC is pushing ahead. A lot of the research that has shown that there is no link between vaccines and autism comes from the CDC itself.

I’m not one to invent conspiracies, but this study was set up right after Robert F Kennedy Jr took over Health and Human Services, which oversees the CDC. I am just connecting the dots.

This post will examine the facts about another study examining the links between vaccines and autism and the potential direction the CDC research could explore. They will probably not find anything unless they fill the research with biases and unscientific analyses.

autism vaccines

This image made from television from NBC’s “Today Show” shows Dr. Andrew Wakefield during an interview on May 24, 2010, in New York with host Matt Lauer. (AP Photo/NBC’s Today Show)

The story of vaccines and autism pseudoscience

In case you are just now hearing about this debunked vaccines and autism link, here’s a brief history of how we got here.

Vaccines were first blamed for the link to autism in 1998 when Mr. Andrew Wakefield published his fraudulent study on vaccines and autism, a paper that was subsequently retracted.

Despite this, and the massive number of scientific studies that have shown no link between any vaccine and autism, RFK Jr has made many debunked false claims that vaccines cause autism. Kennedy has linked autism to vaccines in at least 36 appearances, despite the evidence that refutes his beliefs.

Also, Kennedy’s boss, President Trump, seems to believe in this unfounded link between vaccines and autism.

Kennedy also pushes that thimerosal, a preservative that is only used in some multidose vials of vaccines to prevent contamination, causes autism. This has also been debunked. According to the FDA, all vaccines routinely recommended for children six years and younger in the USA do not contain thimerosal.

I remember a discussion I had with someone years ago when I kept updating my article on vaccines and autism with newly published research, and they said “no one talks about autism and vaccines anymore.” Wrong.

CDC autism vaccines study

There is no link between vaccines and autism

1 – Scientific studies

Currently, the CDC website (image above) states, without reservation, that there is no link between vaccines and autism. The National Academy of Medicine, one of the most prestigious scientific bodies in the world, states there is no link between vaccines and autism. Over 160 peer-reviewed and published scientific studies show that there is no link between vaccines and autism.

A large CDC study showed that there was no increased risk of autism irrespective of the number of antigens given with vaccines over the first two years of life.

A large retrospective analysis of more than 537,000 children in Denmark showed the risk of autism diagnosis was similar between those who received the MMR vaccine and those who did not.

2 – Plausibility

One of the important steps to determining whether vaccines are causal to autism is the important principle of biological plausibility. In epidemiology, biological plausibility ranks near the top of the list of criteria to make a claim of causality between cause and effect. This is something that is forgotten or intentionally ignored by those pushing a link between vaccines and autism.

That being said, is there a plausible science-based mechanism that links vaccines to autism?

There isn’t one. The vaccine’s sole biological action is to induce the immune system to remember antigens on the pathogen so that it can quickly attack it before it causes an infection. The action happens over a short period because the immune system works quickly. Once the vaccine boosts the immune system, it quickly leaves the body.

There is simply no plausible pathway for a vaccine to affect neurological development. Vaccines, including the ingredients in vaccines, do not have a biological effect on the brain.

If someone wants to make a convincing argument that vaccines cause autism, they need to provide a science-based mechanism that makes sense temporally and biologically. So far, no one has provided a potential mechanism that does not take leaps of logic.

3 – What causes autism?

Two general factors are linked to autism, and neither are vaccines.

First, autism is highly genetically heterogeneous, with hundreds of genes identified that contribute to the disorder. These include inheritable and de novo gene variations, which account for 10-20% of cases. Other researchers have found that genetic factors are estimated to contribute up to 80% of ASD cases, with de novo mutations accounting for about 30%.

Second, environmental factors such as maternal infections, heavy metal exposure, and prenatal infections have been implicated in ASD. These factors can disrupt immune function and synaptic transmission. In addition, prolonged immune activation and inflammation during pregnancy, such as influenza, have been linked to ASD.

The risk of developing autism doesn’t occur when children get vaccines, it happens in utero.

ASD arises from a complex interplay of genetic and environmental factors. While genetic predispositions play a significant role, environmental influences and their interactions with genetic factors are also critical in understanding the etiology of autism.

light on computer hardware

Photo by panumas nikhomkhai on Pexels.com

What is the CDC going to study about vaccines and autism?

Another report indicated that the CDC plans to assess whether a relationship between vaccines and autism exists using information from the Vaccine Safety Datalink (VSD). The VSD is a collaborative project, established in 1990, between the CDC and several US healthcare organizations to monitor vaccine safety and to study rare and serious adverse events. The VSD uses electronic health record data from member sites to assess vaccine safety and detect adverse events in near-real time.

VSD is a vastly better database for vaccine safety than the Vaccine Adverse Events Reporting System (VAERS), which is a self-reported system that cannot establish causation between vaccines and any adverse event.

I would be shocked if this new study would provide any evidence of a link between vaccines and autism. Other researchers have used VSD to examine potential links between vaccines and autism, and they have found nothing.

A 2022 VSD study of over 1,665,000 children found no link between pertussis vaccines and autism.

A 2022 VSD study of nearly 85,000 children found no link between influenza vaccines and autism.

A 2018 VSD study of nearly 600,000 children actually found that children with ASD were under-vaccinated compared to children without ASD.

A 2007 VSD study did not support a causal association between early exposure to mercury from thimerosal-containing vaccines and neuropsychological functioning at ages 7 to 10 years.

The VSD has been used to debunk the claims that vaccines cause autism, and unless the CDC decides to create some weird protocol and analysis that biases the results, I don’t see how we will get any different results than we already have. If the CDC does find some contradictory evidence, it will be published, and scientists will pore over the data and analysis to determine if it is reasonable.

white and green scrabble tiles on the table

Photo by Polina ⠀ on Pexels.com

My thoughts about this

My thoughts are pretty simple — why is the CDC wasting time and money on another study that will almost definitely not show that vaccines are linked to autism? I’m a scientist, so I am open-minded to new evidence, but we have wasted billions of dollars searching for this nonexistent link.

Moreover, this money could be better spent on understanding the real causes of autism and how we can support parents of autistic children. The billions of dollars chasing down this link could have been better spent to help understand autism.

Somehow, I feel like this type of research demonizes autism. People like RFK Jr want us to believe that neurodivergent people should be stigmatized, and by blaming vaccines, they can “prove” why autistic children are the way they are.

We should be doing better than that, especially the CDC.

Note

This is a revised version of an article posted on 9 March 2025. It adds more information about why vaccines are not linked to autism which was mistakenly deleted from the older article. The older article will redirect to this one.

Citations

Becerra-Culqui TA, Getahun D, Chiu V, Sy LS, Tseng HF. Prenatal Influenza Vaccination or Influenza Infection and Autism Spectrum Disorder in Offspring. Clin Infect Dis. 2022 Sep 30;75(7):1140-1148. doi: 10.1093/cid/ciac101. PMID: 35174388.

Cracking the mystery of autism spectrum disorder. EBioMedicine. 2020 Feb;52:102691. doi: 10.1016/j.ebiom.2020.102691. PMID: 32089274; PMCID: PMC7033517.

DeStefano F, Price CS, Weintraub ES. Increasing exposure to antibody-stimulating proteins and polysaccharides in vaccines is not associated with risk of autism. J Pediatr. 2013 Aug;163(2):561-7. doi: 10.1016/j.jpeds.2013.02.001. Epub 2013 Mar 30. PMID: 23545349.

Gerber JS, Offit PA. Vaccines and autism: a tale of shifting hypotheses. Clin Infect Dis. 2009 Feb 15;48(4):456-61. doi: 10.1086/596476. PMID: 19128068; PMCID: PMC2908388.

Madsen KM, Hviid A, Vestergaard M, Schendel D, Wohlfahrt J, Thorsen P, Olsen J, Melbye M. A population-based study of measles, mumps, and rubella vaccination and autism. N Engl J Med. 2002 Nov 7;347(19):1477-82. doi: 10.1056/NEJMoa021134. PMID: 12421889.

Rylaarsdam L, Guemez-Gamboa A. Genetic Causes and Modifiers of Autism Spectrum Disorder. Front Cell Neurosci. 2019 Aug 20;13:385. doi: 10.3389/fncel.2019.00385. PMID: 31481879; PMCID: PMC6710438.

Thompson WW, Price C, Goodson B, Shay DK, Benson P, Hinrichsen VL, Lewis E, Eriksen E, Ray P, Marcy SM, Dunn J, Jackson LA, Lieu TA, Black S, Stewart G, Weintraub ES, Davis RL, DeStefano F; Vaccine Safety Datalink Team. Early thimerosal exposure and neuropsychological outcomes at 7 to 10 years. N Engl J Med. 2007 Sep 27;357(13):1281-92. doi: 10.1056/NEJMoa071434. PMID: 17898097.

Wakefield AJ, Murch SH, Anthony A, Linnell J, Casson DM, Malik M, Berelowitz M, Dhillon AP, Thomson MA, Harvey P, Valentine A, Davies SE, Walker-Smith JA. Ileal-lymphoid-nodular hyperplasia, non-specific colitis, and pervasive developmental disorder in children. Lancet. 1998 Feb 28;351(9103):637-41. doi: 10.1016/s0140-6736(97)11096-0. Retraction in: Lancet. 2004 Mar 6;363(9411):750. doi: 10.1016/S0140-6736(04)15715-2. Retraction in: Lancet. 2010 Feb 6;375(9713):445. doi: 10.1016/S0140-6736(10)60175-4. PMID: 9500320.

Zerbo O, Modaressi S, Goddard K, Lewis E, Fireman BH, Daley MF, Irving SA, Jackson LA, Donahue JG, Qian L, Getahun D, DeStefano F, McNeil MM, Klein NP. Vaccination Patterns in Children After Autism Spectrum Disorder Diagnosis and in Their Younger Siblings. JAMA Pediatr. 2018 May 1;172(5):469-475. doi: 10.1001/jamapediatrics.2018.0082. PMID: 29582071; PMCID: PMC5875314.

Zerbo O, Modaressi S, Goddard K, Lewis E, Fireman B, Daley MF, Irving SA, Jackson LA, Donahue JG, Qian L, Getahun D, DeStefano F, McNeil MM, Klein NP. Safety of measles and pertussis-containing vaccines in children with autism spectrum disorders. Vaccine. 2022 Apr 20;40(18):2568-2573. doi: 10.1016/j.vaccine.2022.03.031. Epub 2022 Mar 18. PMID: 35315325; PMCID: PMC10987202.

Michael Simpson

Lifetime lover of science, especially biomedical research. Spent years in academics, business development, research, and traveling the world shilling for Big Pharma. I love sports, mostly college basketball and football, hockey, and baseball. I enjoy great food and intelligent conversation. And a delicious morning coffee!