FactCheck.org claims that the mercury in vaccines is harmless and science has proven vaccines don’t cause autism, but its own key source says otherwise.

On December 11, 2018, Mark Green, a member-elect of the US House of Representatives from Tennessee and a physician, told a town hall audience, “Let me say this about autism. I have committed to people in my community, up in Montgomery County, to stand on the CDC’s desk and get the real data on vaccines. Because there is some concern that the rise in autism is the result of the preservatives that are in our vaccines.”

By saying that he intended to push the CDC on the question of whether vaccines—and specifically the mercury-containing preservative thimerosal—might be contributing to the autism epidemic, Green committed the sin of heresy against the vaccine religion, and the mainstream corporate media was quick to attack him for it. The suggestion that vaccines might cause autism is “baseless”, declared CBS News. Green made the claim “falsely”, declared CNN.

The website FactCheck.org also dutifully got in on the act with an article by Jessica McDonald stating that Green “inaccurately claimed that vaccine preservatives might cause autism.” His statement, McDonald writes, was “bogus”.

To counter Green’s ostensibly “bogus” claim, McDonald writes (bold emphasis added):

Multiple large studies already have investigated whether any aspect of vaccination — including preservatives — can cause autism and found no evidence they do. The CDC alone has conducted nine investigations into the preservative thimerosal, finding no link to the disease….

Green’s suggestion that vaccine preservatives could be behind the “rise in autism” is not backed by science.

As the CDC says on its website, “there is no link between vaccines and autism,” and “vaccine ingredients do not cause autism.” And in fact, as we have written beforeit is not necessarily clear that there has been a rise in autism. There certainly have been more reported cases in recent years, but during that time the definition expanded and awareness increased.

Then McDonald explains that the concern about thimerosal is the fact that it contains mercury. Specifically, thimerosal is about half ethylmercury by weight and is used in multi-dose vials of vaccines to prevent contamination. It was included in numerous childhood vaccines until the decision was made in 1999 to remove it from most. It is still used in multi-dose flu vaccines, which the CDC recommends for children as young as six months as well as pregnant women.

After explaining that the concern is related to the use of mercury in vaccines, McDonald continues (emphasis added):

Although the phrase “mercury-containing” might sound scary, thimerosal has a stellar safety record. Not only is the amount of mercury in a vaccine extremely small, but it’s also a type known as ethylmercuryThis type of mercury is different from methylmercury, which is the form that accumulates in fish and is toxic to people. Ethylmercury is broken down in the body much more quickly, so it poses less of a risk.

The thimerosal in vaccines is only thought to be dangerous if a person has an allergy to the chemical, and that’s rare. The side effects are minor: a little bit of redness and swelling at a vaccine injection site.

I have preserved McDonald’s links to her sources in the above quotes from her FactCheck.org article. As you can see, so far, she has relied entirely on information the CDC presents to the public on its website—apart from the suggestion that the increase in autism prevalence is a statistical artifact, not real, which we’ll come back to.

You can click the links and verify for yourself that she is representing the CDC’s information accurately.

After taking the CDC’s word for it that science has demonstrated that vaccines do not cause autism and that the form of mercury in vaccines, unlike methylmercury, is not toxic, McDonald, feigning due diligence, cites some references from the scientific literature, including an Institute of Medicine report that the CDC also relies on to support its claims. She writes (emphasis added):

Numerous studies specifically have looked at thimerosal and autism. In 2004, the Institute of Medicine, which is now known as the Health and Medicine Division of the National Academies, reviewed the evidence and rejected a causal relationship between thimerosal-containing vaccines and autism. A 2006 study of nearly 28,000 children in Canada found pervasive developmental disorders were actually more common in the kids who received thimerosal-free vaccines — and concluded that the amount of thimerosal exposure was “unrelated” to the increasing reports of such disorders.

The CDC also published nine investigations between 2003 and 2012 that failed to find a connection between thimerosal and autism. Two of these studies observed that autism rates continued to increase in countries such as Denmark and Sweden even when thimerosal was decreased or removed from vaccines.

Finally, McDonald explains the removal of thimerosal from most childhood vaccines by writing (emphasis added):

Indeed, despite a lack of serious safety concerns, the United States decided to begin removing thimerosal from childhood vaccines in 1999, and today all vaccines for children ages 6 and younger are available without thimerosal. This, however, was not done because of concerns about autism. As the CDC explains, “This was done as part of a broader national effort to reduce all types of mercury exposure in children before studies were conducted that determined that thimerosal was not harmful. It was done as a precaution.” And consistent with the data in other countries, reported autism rates in America have continued to rise despite thimerosal removal.

So now let’s fact-check FactCheck.org’s—and by extension, the CDC’s—claims about vaccine safety.

The Safety of the CDC’s Childhood Vaccine Schedule Has NOT Been Scientifically Demonstrated

First, McDonald’s claim that numerous large studies have examined whether “any aspect of vaccination” can cause autism is a bald-faced lie.

In fact, it is such a bold lie, we can see that her claim is false by turning to her own key source from the scientific literature: the 2004 IOM report, which reviewed the available studies, including those conducted by the CDC.

It is true that the IOM report concluded that the weight of scientific evidence supported the rejection of the hypothesis that vaccines can cause autism. However, far from investigating whether “any aspect of vaccination” might increase the risk of autism, what the IOM review showed was that the studies that had been done to date had only considered one combination vaccine (the measles, mumps, and rubella, or MMR vaccine) and one vaccine ingredient (thimerosal).

Of course, concerns about the harms of vaccination are not limited to concerns only about the MMR vaccine or the use of thimerosal and whether either of those might cause autism. There are concerns about all the vaccines, both individually and cumulatively. These concerns are not limited to fears about autism, but numerous other diseases, as well, including the alarming increases in a wide range of autoimmune diseases and other developmental disorders. They are not limited to concerns about mercury, but also numerous other vaccine ingredients, including aluminum.

Today, if following the CDC’s recommended routine childhood vaccine schedule, children can be exposed to as many as 43 doses of 10 vaccines by age six—two of which are combination vaccines containing three vaccine doses each (MMR and the diphtheria, tetanus, and pertussis, or DTaP vaccine).

And, as we can learn by examining FactCheck.org’s own primary source from the literature, the studies that have been done to investigate whether there might be an association between vaccines and autism have only considered one of them.

They have only considered one vaccine ingredient, despite concerns about numerous other ingredients, including human DNA from aborted fetal tissue, animal DNA, and aluminum. There are also concerns about contamination, such as with retroviruses, which are well founded because such contamination has happened before, such as the discovery of a monkey virus in polio vaccines and pig viruses in rotavirus vaccines.

Far from numerous studies having investigated whether “any aspect of vaccination” might be associated with autism, as another report by the IOM in 2013 explicitly acknowledged, “existing research has not been designed to test the entire immunization schedule”. The IOM reiterated, “studies designed to examine the long-term effects of the cumulative number of vaccines or other aspects of the immunization schedule have not been conducted.” (Emphasis added.)

That is to say, the safety of the CDC’s routine childhood vaccine schedule has not been scientifically demonstrated. It is merely assumed. People who believe it is safe do so not based on science, but on faith.

The Studies Cited by the CDC Ignore Genetic Susceptibility

Furthermore, one of the biggest concerns about public vaccine policy is that it is a one-size-fits-all approach to disease prevention that puts at risk children who might have a genetically or environmentally caused predisposition to vaccine injury.

That vaccines do cause injuries to some children is completely uncontroversial. In fact, the government administrates a Vaccine Injury Compensation Program (VICP) to assist families of vaccine-injured children.

This was established under a 1986 law by which the government granted broad legal immunity from vaccine injury lawsuits to manufacturers of vaccines on the CDC’s routine childhood schedule.

The Supreme Court in 2011 upheld legal immunity for vaccine manufacturers on the grounds that certain adverse reactions to vaccines are “unavoidable” and “design defects” are “not a basis for liability.” It is precisely the “unavoidability” of a given vaccine injury that establishes “a complete defense” against lawsuits, given that the vaccine was properly prepared and was accompanied with adequate warnings (which are found in the manufacturer’s package inserts).

The VICP is funded by an excise tax on each vaccine dose. The tax is nominally paid by the manufacturers, but is included in the purchasing price paid by consumers. In effect, the VICP shifts the financial burden for vaccine injuries away from the pharmaceutical companies and onto the taxpaying consumers.

Furthermore, the US government has acknowledged that some children may be at greater risk of vaccine injury than others.

One famous VICP case was that of Hannah Poling, who regressed into autism after receiving nine vaccine doses (five vaccines, including the DTaP and MMR combination shots), all at once at 19 months of age. In that case, the government conceded that (emphasis added):

the facts of this case meet the statutory criteria for demonstrating that the vaccinations CHILD received on July 19, 2000, significantly aggravated an underlying mitochondrial disorder, which predisposed her to deficits in cellular energy metabolism, and manifested as a regressive encephalopathy with features of autism spectrum disorder.

Then CDC Director Julie Gerberding publicly acknowledged (emphasis added):

Now, we all know that vaccines can occasionally cause fevers in kids. So if a child was immunized, got a fever, had other complications from the vaccines. And if you’re predisposed with a mitochondrial disorder, it can certainly set off some damage. Some of the symptoms can be symptoms that have characteristics of autism.

Of course, by acknowledging that vaccines can cause “symptoms that have characteristics of autism”, the CDC director really meant “autism”, since autism is a disease diagnosed solely on the basis of it symptoms, and since she was referring specifically to the case of Hannah Poling, who was diagnosed with autism after her developmental regression following vaccination.

One of the CDC’s own lead researchers, who headed up a number of the studies that the CDC cites to support its claim that vaccines do not cause autism, is Dr. Frank DeStefano, the longtime director of the CDC’s Immunization Safety Office. In a 2014 interview, DeStefano acknowledged that “it’s a possibility” that vaccines could trigger autism in genetically susceptible individuals, but the problem is it’s “hard to predict who those children might be”, and trying to determine what underlying conditions put children at risk of vaccine injury is “very difficult to do”.

Returning once again to FactCheck.org’s own source, the 2004 IOM report, it in fact acknowledged that none of the studies it reviewed were actually designed to test the hypothesis that vaccines administered according to the CDC’s routine childhood schedule can cause autism in genetically susceptible subpopulations.

“This hypothesis”, the IOM pointed out, “cannot be excluded by epidemiological data from large population groups that do not show an association between a vaccine and an adverse outcome.”

The type of study that would be needed in order to be able to rule out any association to any reasonable degree of certainty is the randomized, placebo-controlled trial, which haven’t been done. The retrospective observational studies that have been done are prone to selection biases and can’t control for all the innumerable variables as well as randomized controlled trials, which is why the latter design is the gold standard for safety studies.

Furthermore, none of the studies reviewed by the IOM were designed to test the hypothesis that there might be genetically susceptible subpopulations. The IOM acknowledged that this provides “a theoretical explanation for the data presented in this report”—that is to say, the IOM acknowledged that existing studies had not ruled out the hypothesis for the simple reason that they weren’t designed to test it.

To further illustrate what a bald-faced lie it is for FactCheck.org to state that numerous large studies have examined whether “any aspect of vaccination” is associated with autism, consider the fact that none of these studies considered the possibility of synergistic toxicity between the mercury and the aluminum that children are also exposed to from vaccines.

Ethylmercury is a Known Neurotoxin That Accumulates in the Brain

FactCheck.org’s bald-faced lies about the science don’t end there. While it’s true that the CDC claims on its website that the mercury in vaccines is “very safe” to inject into children and pregnant women, the truth is that ethylmercury, like methylmercury and aluminum, is a known neurotoxin.

Recall that McDonald simply parroted the CDC’s own claims that the ethylmercury in vaccines, unlike the methylmercury found in fish and other environmental sources of exposure, is not toxic and is rapidly eliminated from the body.

Yet the very IOM review cited by both the CDC and FactCheck.org to support these claims actually described thimerosal as a “known neurotoxin”, acknowledged that some of the mercury from vaccines “accumulates in the brain”, and admitted that “heavy metals, including thimerosal, can injure the nervous system.” (All emphasis added.)

As another illustration of how, by lying to the public about what the science says, the media are simply following the CDC’s example, another source cited by the CDC to support its claims is a study published in 2005 in Environmental Health Perspectives.

Yet once again turning to the CDC’s own source, we can see that, in fact, that very study actually found that ethylmercury breaks down more easily into inorganic mercury and thus is more persistent in the brain than methylmercury, an organic form that is more easily eliminated. Furthermore, they observed that inorganic mercury in the brain has been “associated with a significant increase in the number of microglia in the brain” and that “‘an active neuroinflammatory process’ has been demonstrated in brains of autistic patients, including a marked activation of microglia.” (Bold emphasis added.)

In their concluding remarks, they further expressed dismay that the IOM, in its 2004 report, implicitly recommended that further research not be undertaken to test the biologically plausible hypothesis that vaccines can cause autism: “This approach is difficult to understand, given our current limited knowledge of the toxicokinetics and developmental neurotoxicity of thimerosal, a compound that has been (and will continue to be) injected into millions of newborns and infants.”

Far from supporting the CDC’s claim that science has shown that mercury exposure from vaccines is “very safe”, the CDC’s very own source actually concluded that more research into the neurotoxic potential of thimerosal and its breakdown product ethylmercury was “urgently needed” to be able to draw any meaningful conclusions about “the potential developmental effects of immunization with thimerosal-containing vaccines in newborns and infants.”

To cite just a few other studies highlighting the falsehood of the CDC’s claims about ethylmercury being rapidly and harmlessly eliminated from the body, a 2004 rodent study by National Institutes of Health (NIH) researchers published in Toxicology Letters similarly found that, while ethylmercury is readily eliminated from the blood, it is persistent in the tissue, the kidneys, and the brain.

A team of Italian researchers published a study in Interdisciplinary Toxicology in 2012 finding that thimerosal is fifty times more toxic than methylmercury to human cells in terms of the dose required to significantly decrease cellular viability or induce cell death. As they concluded, “Our findings demonstrate that thimerosal at the concentration usually found in vaccines, affects significantly cellular viability.”

A meta-analysis of available studies on low-dose thimerosal exposure published in Neurochemical Research in 2011 observed that all such studies had found evidence of neurotoxicity. Furthermore, no studies had considered the synergistic toxicity of thimerosal-containing vaccines being administered concomitantly with aluminum-containing vaccines. Animal studies had shown that thimerosal exposure results in accumulation of inorganic mercury in the brain. Finally, at doses relevant to the exposure children receive from the CDC’s schedule, thimerosal’s demonstrated neurotoxicity “possesses the potential to affect human neuro-development.”

The cumulative exposure to thimerosal that pregnant women and infants get from vaccines, the study concluded, “is a likely risk factor for neurodevelopmental delays that has yet to be defined.” There may also be “subtle neurodevelopmental delays in susceptible infants” that “may not be perceived in routine medical examinations.” The evidence that low doses of thimerosal from vaccines “can affect neural tissues and functions” is “unequivocal”. Consequently, “use of thimerosal in vaccines should be reconsidered by public health authorities, especially in those vaccines intended for pregnant women and children.”

The science is absolutely clear: ethylmercury is a known neurotoxin that accumulates in the brain and kidneys and damages human cells at doses relevant to the CDC’s routine childhood vaccine schedule.

The CDC’s claim that ethylmercury, unlike methylmercury, is not toxic and that it cannot cause harm because it is readily eliminated from the body is a deliberate lie.

Lazy-ass journalists working for mainstream publications then echo and broadcast that lie to the public in service to the state, engaging in public policy advocacy rather than journalism.

It’s important to recognize that when the media so grossly misinform the public about vaccine safety, they are simply following the CDC’s example.

The Problem with Observational Studies

As mentioned, one problem with observational studies is that they are prone to selection bias. FactCheck.org actually presents an apparent example of this with the second study McDonald cites to support her assertion that science has falsified the hypothesis that vaccines can cause autism: the 2006 Canadian study that “found pervasive developmental disorders were actually more common in the kids who received thimerosal-free vaccines” (emphasis added).

It is notable that the authors concluded merely that there was no association between thimerosal and autism rather than concluding that thimerosal is associated with a decreased risk of autism.

One obvious reason for that is the lack of biological plausibility that injecting children with a known neurotoxin protects them from neurological damage.

Yet the authors of that study made no effort to explain their finding of a negative association.

However, there is a very simple and obvious explanation—and it’s one that would completely invalidate their findings.

The explanation is not that thimerosal exposure is associated with a decreased risk of autism, but that an eventual autism diagnosis is associated with a decreased use of thimerosal-containing vaccines.

It is only natural that parents concerned about abnormal behavior or neurological symptoms would take extra precautions, like choosing thimerosal-free vaccines.

Supporting this explanation, a study published in March 2018 in JAMA Pediatrics found that children with autism and their younger siblings are less vaccinated than the general childhood population. Once again, the obvious explanation for this is that parents who are concerned about the neurological development of their children are more likely to avoid certain or even all vaccines.

This type of selection bias is sometimes described as a “healthy user” bias, and it is one of the problems with relying on observation studies rather than conducting proper randomized controlled safety trials.

The Increase in Autism Prevalence Is Real

According to the CDC’s most recent estimate, the prevalence of autism among children aged eight in the US today is an alarming 1 in 59.

FactCheck.org’s claim that the perceived increase in the prevalence of autism may be entirely a statistical artifact, not real, is disingenuous. It is true that there remains considerable controversy about the extent to which changes in diagnostic criteria and greater awareness have contributed to the perceived increase; but not whether prevalence has increased.

For example, one of the studies FactCheck.org cites to support the contention that there may not even be more autism today than there was fifty years ago is a 2010 study in Research in Autism Spectrum Disorders that concluded the increased prevalence can only be “partly supported” by factors related to diagnostic trends. The question, the authors noted, is not over whether but “how much of a real increase in prevalence has occurred” (emphasis added).

A 2009 study published in Epidemiology by researchers from UC Davis examined prevalence of autism in California and found that “the incidence of autism rose 7- to 8-fold in California from the 1990s through the present”, from fewer than 9 in 10,000 for children born in 1990 to more than 44 in 10,000 for children born in 2000, with “no sign yet of plateauing”. Furthermore, changes in diagnostic criteria could not explain the full magnitude of the increase. The authors concluded that the rising rate of autism truly represents “a major public health and educational concern.”

As the UC Davis press release observed, the study “found that the seven- to eight-fold increase in the number children born in California with autism since 1990 cannot be explained by either changes in how the condition is diagnosed or counted — and the trend shows no sign of abating.”

As autism researcher Irva Hertz-Picciotto commented, “It’s time to start looking for the environmental culprits responsible for the remarkable increase in the rate of autism in California”.

A study published in June 2018 in the Journal of Autism and Developmental Disorders examined this question by looking at autism prevalence in California using a dataset that “continues to exclude most milder cases of autism, despite two different changes to its diagnostic criteria in the last decade”. They found that prevalence slowly increased from about 1940, and the rate of autism “gradually accelerated over time” until 1980, when there was an uptick, followed by continued increase and additional upticks in 1990 and 2007. The prevalence of autism “increased from 0.001% in the cohort born in 1931 to 1.2% among 5 year-olds born in 2012.”

Dismissing parental concerns about the use of a known neurotoxin in vaccines by claiming that there may not even be an increased prevalence of autism as more and more vaccines have been added to the schedule is simply insincere.

The Real Reason Thimerosal Was Removed from Most Childhood Vaccines

Finally, FactCheck.org claims that thimerosal was removed from most childhood vaccines “despite a lack of serious safety concerns”.

That, too, is a bald-faced lie.

On the contrary, this decision was made because (1) it was economically viable for vaccine manufacturers to do so and (2) it had become known that, as the CDC added more thimerosal-containing vaccine doses to the schedule, no government agency ever bothered to calculate the cumulative levels of mercury that children were being exposed to, and when the FDA finally got around to doing so, it determined that the levels exceeded the safety guidelines determined by the Environmental Protection Agency (EPA).

This finding was reported in a 2001 study published in Pediatrics by FDA researchers who also acknowledged that “no controlled studies have been conducted to examine low-dose thimerosal toxicity in humans” and conceded that “we cannot exclude the possibility of subtle neurodevelopmental abnormalities from the cumulative exposure to thimerosal in vaccines”. (Bold emphasis added.)

That study, too, is cited by the CDC to support its claim that thimerosal is “very safe” to inject into children and pregnant women, whom the CDC advises get a flu shot during any trimester even though the CDC’s own researchers have found that women vaccinated two years in a row with vaccines containing a pandemic influenza A(H1N1) antigen had a statistically significant 7.7 times greater risk of having a miscarriage.

The CDC researchers pointed out in their study, which was published in Vaccine in September 2017, that it was an observational study and thus does not establish that the vaccine actually causes miscarriages, although they did not identify any other more plausible explanation for the found association.

It’s also worth noting that, when harms are found to be associated with vaccines, we are told that observational studies aren’t evidence of a causal relationship, and yet when no association between vaccines and autism are found, we are told that observational studies are absolutely determinative in disproving any possible causal association!

This is a stark illustration of the level of cognitive dissonance that exists in the mainstream discourse about vaccines.

The reason the FDA finally got around to doing the calculations to determine how much mercury children were being exposed to from vaccines was because in 1997, Congress passed the FDA Modernization Act, a provision of which required the FDA to compile a list of mercury-containing drugs on the market. The products included in the industry’s responses to the FDA’s inquiry included more than 30 licensed vaccines. When the FDA’s Center for Biologics Evaluation and Research (CBER) did the calculations showing mercury exposure in excess of the EPA’s guidelines, government officials waffled over what to do about it. In a 1999 email to the acting director of the CDC’s National Vaccine Program Office, Martin Meyers, the director of the FDA’s Division of Viral Products, Dr. Peter Patriarca, opined that to call for the removal of thimerosal from vaccines would

raise questions about FDA being ‘asleep at the switch’ for decades by allowing a potentially hazardous compound to remain in many childhood vaccines, and not forcing manufacturers to exclude it from new products. It will also raise questions about various advisory bodies regarding aggressive recommendations for use. (We must keep in mind that the dose of ethylmercury was not generated by “rocket science”. Conversion of the percentage thimerosal to actual micrograms of mercury involves ninth grade algebra. What took the FDA so long to do the calculations? Why didn’t CDC and the advisory bodies do these calculations when they rapidly expanded the childhood immunization schedule?)

It’s not surprising that the CDC, too, states on its website that the decision was made in 1999 to remove thimerosal from most childhood vaccines while withholding the fact that the reason this decision was made was because the CDC was exposing children to higher levels of mercury than the government itself had judged was safe.

After all, to disclose that relevant information might cause members of the public to reasonably conclude that they cannot trust government agencies like the CDC and FDA.


Serious discussion in the mainstream media about the critically important issue of vaccines does not exist. Instead of educating people to be able to make informed choices about vaccinations, the media instead grossly misinform the public, engaging in public policy advocacy rather than doing journalism. The type of blatant lying you’ve witnessed here when it comes to the subject of vaccines is routine and systematic. Lying about the science so long as the purpose is to instill faith and confidence in public vaccine policy is considered perfectly acceptable.

In so deceiving the public, the media are simply following the example set by the CDC.

The demonstrable truth of the matter is that what the government and media say science says about vaccines and what science actually tells us are two completely different and contradictory things. It is well past time that the media started doing real journalism, and it is well past time that public health officials started taking parents’ concerns seriously.

This article was originally published at JeremyRHammond.com.