Did a New Study Find That Vaccines With Thimerosal is Associated With Autism?
A study that neglected to consider the declining percentage flu shots containing thimerosal?
Why so some folks think that a new study has found that vaccines with thimerosal are associated with autism?
The usual suspects…
Did a New Study Find That Vaccines With Thimerosal is Associated With Autism?
In this case, Children’s Health Defense, the anti-vaccine organization that RFK Jr founded, is promoting a new study by one of their own writers.
A researcher who claims she has no conflicts of interest, despite being an Executive Board Member of the SafeMinds Environmental Committee, an anti-vaccine organization that has long promoted that idea that mercury in vaccines has been causing vaccine injuries.
A new study published in an IPAK journal of James Lyons-Weiler, whose editorial board is a who’s who of anti-vaccine influencers.
Do you even need to know what’s wrong with the study at this point?
A study about vaccines, thimerosal, and autism…
“The sharp drop in the ID fraction between birth year 2000 and 2002 coincided with the removal of thimerosal, a mercury-containing preservative and neurotoxin linked to autism severity, from most childhood vaccines. Conversely, the renewed increase in the ID fraction after 2006 coincided with the reintroduction of thimerosal via flu shots promoted for infants and pregnant women.”
Time Trends in United States Autism Prevalence with Co-Occurring Intellectual Disability: Is There a Signature of Thimerosal?
No, she is not saying that fewer autistic kids were diagnosed in these years.
“ID fraction refers specifically to the percentage of total ASD cases with IQ < 70. The ID fraction is used here as the metric of autism severity.”
Time Trends in United States Autism Prevalence with Co-Occurring Intellectual Disability: Is There a Signature of Thimerosal?
She is saying that there were fewer autistic kids with lower IQs after thimerosal was removed from vaccines, at least until some of those kids might have gotten flu vaccines with thimerosal.
The problem with her theory?
Well, for one thing, although there was a call for thimerosal to be removed from most childhood vaccines in 1999, it wasn’t an immediate thing.
It took a minute for thimerosal free versions of these vaccines to be developed.
For example, while we got a thimerosal free hepatitis B vaccine in March 2000, it took a longer, in March 2001, to get all of our DTaP vaccines to be thimerosal free and 2003 for thimerosal free flu vaccines. And we didn’t just throw out our vaccines with thimerosal. They were used up.
So it is unlikely that all of those infants in 2000 had thimerosal free vaccines.
In fact, many likely had flu vaccines with thimerosal, as the first recommendation for infants to get a flu vaccine was issued in 2002, just before thimerosal free flu vaccines came out.
“Conversely, the renewed increase in the ID fraction after 2006 coincided with the reintroduction of thimerosal via flu shots promoted for infants and pregnant women. Low-income women and children are particularly likely to receive those products in some states, due to health insurance and daycare requirements, which may be contributing to autism severity as well as to the recent strong divergence in ASD prevalence by race/ethnicity.”
Time Trends in United States Autism Prevalence with Co-Occurring Intellectual Disability: Is There a Signature of Thimerosal?
And she has no good reason to suspect that many of these children actually got flu vaccines with thimerosal in later years, especially since thimerosal free flu shots were available.
“Similarly, women served by Medicaid are likely under pressure from their doctors to follow the CDC schedule during pregnancy. They also may be more likely to receive flu shots from thimerosal-containing multi-dose vials, while wealthier women covered by private insurance may have more opportunity to choose thimerosal-free shots from single dose vials.”
Time Trends in United States Autism Prevalence with Co-Occurring Intellectual Disability: Is There a Signature of Thimerosal?
Even low income women and children would have qualified for free flu vaccines without thimerosal via the Medicaid or the Vaccines for Children program.
“Although flu shots for decades, from 1960-2000, had been recommended only for adults aged 65 years or older, the CDC in 2004 recommended the shots for pregnant women in any trimester, as well as for children aged 6 to 23 months.”
Time Trends in United States Autism Prevalence with Co-Occurring Intellectual Disability: Is There a Signature of Thimerosal?
She also ignores all the pregnant women who would have gotten flu vaccines with thimerosal from 2000 to 2002, as the universal flu vaccine recommendation for pregnant women was issued in 1995, not 2004!
What else?
In addition to the fact that the ADDM monitoring sites were undergoing a lot of changes at this time, it is difficult, if not impossible, to use IQ this way.
“Interpreting and summarizing data on IQ distribution in ASD from epidemiological and clinical studies together appears difficult due to several reasons.”
Autism Spectrum Disorder and IQ – A Complex Interplay
For one thing, kids with autism often score differently on different occasions. And some autistic kids can’t complete the IQ tests because of behavioral problems.
And then there are all the studies that have found no association between thimerosal and autism.
Bottom line though, Cynthia Nevison is pushing a correlation between thimerosal in vaccines and autism severity without actually proving that these kids received vaccines with thimerosal.
She provides no evidence for a correlation of getting a vaccine with thimerosal with IQ, and failed to recognize that there is no correlation. Kids from 2000 to 2002 likely got more vaccines with thimerosal than she suspects and kids later, after 2006, almost certainly got less.
In fact, by 2014, while she claims that rates of autism with co-occurring intellectual disability were continuing to rise, the percentage of flu shots with thimerosal had been steadily dropping! They went from about 83% in 2007 all the way down to 23% in 2014.
Now, if there was any kind of correlation with thimerosal, wouldn’t the rates have been dropping as the percentage of flu shots with thimerosal decreased each year?
Lastly, Cynthia Nevison can’t even get it right when she tries to show a correlation between vaccination rates and autism prevalence!
“Perhaps not coincidentally, California had the highest ASD rates in the country in the 2014 ADDM report, with 8% of 8-year-old boys diagnosed.”
Time Trends in United States Autism Prevalence with Co-Occurring Intellectual Disability: Is There a Signature of Thimerosal?
She tries to use California as an example, but fails to mention that many other counties have rather low immunization rates, but come up high in the ADDM reports.
For example, counties in Utah, Missouri, Maryland, and Georgia, with the lowest rates of autism, have immunization rates that aren’t much different from the immunization rates in New Jersey and Tennessee, where you find higher autism rates! And counties in Minnesota, with some of the highest autism rates, have the lowest immunization rates in the ADDM Network!
Overall, this study doesn’t prove a correlation between thimerosal and autism.
It does prove that anti-vaccine influencers will do anything to try and make you think that it does though!
References
Time Trends in United States Autism Prevalence with Co-Occurring Intellectual Disability: Is There a Signature of Thimerosal? https://publichealthpolicyjournal.com/wp-content/uploads/2025/06/Nevison_SciencePublicHealthPolicyAndTheLaw_v7.2019-2025.Jun_2025_fin.pdf
Autism and Developmental Disabilities Monitoring Network Surveillance Year 2000 Principal Investigators; Centers for Disease Control and Prevention. Prevalence of autism spectrum disorders--autism and developmental disabilities monitoring network, six sites, United States, 2000. MMWR Surveill Summ. 2007 Feb 9;56(1):1-11. PMID: 17287714.
Wolff N, Stroth S, Kamp-Becker I, Roepke S, Roessner V. Autism Spectrum Disorder and IQ - A Complex Interplay. Front Psychiatry. 2022 Apr 18;13:856084. doi: 10.3389/fpsyt.2022.856084. PMID: 35509885; PMCID: PMC9058071.
Measuring Intelligence in Autism https://www.kennedykrieger.org/stories/interactive-autism-network-ian/measuring-iq-autism
Nevison' PhD disqualifies her from any medical/vaccine research. She is at UC Boulder and here is what's on her faculty page:
"My research interests include the global biogeochemical cycles of carbon and nitrogen and their impact on atmospheric trace gases, including atmospheric potential oxygen (APO) and the greenhouse gases nitrous oxide (N2O) and carbon dioxide (CO2). I have performed atmospheric inversions of observed N2O to infer source distributions over North America, finding that N2O emissions are concentrated in agricultural regions, particularly the Midwestern corn/soybean belt. My work shows that these emissions occur mainly in springtime coincident with the application of nitrogen fertilizers. My ongoing research seeks to elucidate the overlap of climatic variability with fertilizer and other agricultural management practices to better understand the human and climatic controls on N2O emissions."
Well her paper in Lying Weiler 's phony journal is a lot of gaseous emissions, but it's all gaslighting. Thank for taking down these charlatans.
Your subheading is misleading.
It should more accurately read:
“A study that neglected to consider the declining percentage of flu shots containing thimerosal?”