As the internet's premiere fact-checking site, Snopes is on the frontlines of this era's biggest misinformation battles — from fights against war propaganda to false election-fraud claims to dangerous theories on climate change. Also within that category: The U.S. movement to discredit the effectiveness of vaccinations. Even before 2020, when COVID-19 vaccine skepticism enveloped new shades of otherwise science-minded Americans, Snopes prioritized fact-checking efforts to expose the logical flaws behind anti-vaccine activists' arguments. By unpacking one of their major talking points below, we deepen that work — all with hopes of arming readers with context to discern undisputed facts from agenda-focused mistruths in their everyday lives. If you'd like to support this type of journalism, we'd love your help.
— Jessica Lee, senior assignments editor, snopes.com
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This story explores the history of a purportedly scientific study promoted by Robert Kennedy Jr., a 2024 presidential candidate, and his anti-vaccine non-profit Children's Health Defense. The study purports to "prove" that vaccines are the primary cause of chronic illness in America.
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The study was completed by Joy Garner, an activist with no relevant scientific or medical training. She later recalled she was inspired to investigate the matter while attending a 2019 rally against California vaccine mandates headlined by Kennedy.
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Despite the study's wild and incorrect claims, including that it supposedly demonstrated "the mathematically proven imminent dissolution of America from within," Kennedy and his network of activists gave it wide exposure. In August 2023, he published a book, "Vax-Unvax: Let the Science Speak," featuring the data she collected.
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This story describes the evolution of the claim that the study proved that vaccines are responsible for an "epidemic" of chronic illnesses (like cancer and diabetes), from its birth at a Kennedy rally to its embrace by activists. It is an example of how pseudoscientific health misinformation can mature to reach mainstream audiences with the help of high-profile figures, like Kennedy.
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Kennedy did not respond to our request to comment on the findings of this report, but his "Vax-Unvax" co-author Brian Hooker answered some of our questions on his behalf. Garner engaged in a lengthy back and forth with Snopes, publishing a portion of the exchange on Substack in November 2023.
The Epiphany: 'That's Where The Bodies Are Buried'
In early April 2019, a California woman named Joy Garner said she had an epiphany on the steps of the California State Capitol Building. Standing in a crowd, she was protesting legislation that would place tighter restrictions on doctors who issue medical exemptions for vaccinations. The protest was part of an event organized by leaders of America's anti-vaccine movement, including Robert Kennedy Jr. He gave a headlining speech questioning the safety of vaccines.
"Our research and the litigation that we're doing right now," son of the late Bobby Kennedy and current independent presidential candidate said, referencing the work of his anti-vaccine charity, Children's Health Defense (CHD), "[shows] that many of these vaccines are actually causing, in high probability, far more deaths and injuries than they can ever be argued to be prevented."
These deaths, he suggested in a live stream of the event, were in the form of chronic disease. Life-changing illnesses like cancer and diabetes, according to Kennedy and others, were linked to vaccines.
Robert F. Kennedy Jr. speaks at an anti-Senate Bill 276 rally in Sacramento, California, on April 10, 2019. (Facebook)
Recalling the April 10, 2019, event on a podcast years later, Garner described seeing another protester holding a "clever sign" in the crowd. It referenced, she said, an alleged lack of studies about vaccine safety that include a control group (that is, an unvaccinated group to compare against.) She said she began "howling" to a crowd growing around her.
"They are trying to eliminate the controls because that's where the evidence is," she said to that crowd. Garner believed the alleged superior health of unvaccinated people was direct evidence of harm from vaccines, and that scientists, pharmaceutical companies, and medical professionals were working to keep that fact secret. "That's where the bodies are buried," she recalled saying, referring to information that could be gleaned by comparing the health of unvaccinated and vaccinated people.
Screengrab from Facebook live video taken at an April 24, 2019, anti-SB 276 rally. Sign advertises "thecontrolgroup.org" (Facebook)
Two weeks later, Garner returned to the Capitol for another protest against the California legislation, Senate Bill 276, with printed copies of a survey and supplies for a makeshift booth to advertise her new effort, recruit for participants, and distribute information. (The setup was visible in a Facebook live feed of the event.) This time, her mission was to collect information on the health of as many unvaccinated Americans she could contact. She named her effort The Control Group (TCG).
"Robert Kennedy Jr, and other good people will be able to make good use of this evidence," Garner wrote to potential participants.
The Lawsuit: 'The Most Damning Evidence Big Pharma Has Ever Faced'
Attorneys Greg Glaser (left) and Ray Flores (informedconsentdefense.org)
The data collected by TCG, Garner explained in online recruitments posted in May 2019, would be used to sue the U.S. president and try to end vaccine mandates nationwide. "Our massive and now expanding study," Garner wrote, "will be the most damning evidence big pharma has ever faced in a court of law."
She brought two lawyers on board to fight the federal case in court — Ray Flores and Greg Glaser. Both have deep connections to Kennedy and his anti-vaccine charity, CHD. Kennedy, who, as of this writing, was on leave as chairman and chief legal counsel to the nonprofit to focus on his presidential run, took charge of CHD in 2016.
The CHD advocates for anti-vaccine policies and files lawsuits to advance that goal. Under Kennedy's leadership, the group rode a pre-pandemic wave of anger towards laws mandating vaccines at the state level, such as in California, and became one of the most significant anti-vaccine groups in America. People's objections to mandatory lockdowns and vaccines during the COVID-19 pandemic increased the CHD's reach.
Glaser, The Control Group's lead attorney, has served on the legal team of at least one CHD case and is a regular guest on various shows and podcasts produced by CHD. Flores is presently senior counsel at CHD.
At more than 70 pages, the The Control Group lawsuit repeated the central themes of Kennedy's early April rally and subsequent activism — that the legal protections given to vaccine developers supposedly make it impossible to sue them, and that this alleged immunity means the safety of vaccines is never really tested objectively. "What people don't know," Kennedy misleadingly claimed at the April 10 protest, "is that not only are they exempt from liability, but they're also exempt from safety testing." Also, he accused the manufacturers of lacking long-term safety monitoring.
Kennedy and anti-SB 276 demonstrators at the California Capitol Building, Aug. 28, 2019 (Sacramento Bee)
The Control Group set out to change that. The group attempted to survey as many completely unvaccinated people as possible about whether they suffered from any long-term chronic conditions. First, Garner approached participants at SB 276 rallies and other anti-vaccine events. Later, she reached out to people online. She finished collecting and tabulating the data by July 2020, after receiving responses from over 1,400 people who said they had never been vaccinated.
In November 2020, the group filed its suit against the president — at the time, Donald Trump — in the U.S. Circuit Court for California's Eastern District. The judge switched the plaintiff to Joe Biden following his inauguration in January 2021.
The group's complaint asked a judge to declare specific protections for unvaccinated people, force Biden to establish a national informed consent law, and end mandatory vaccinations nationwide. The group further stated that it sought to prevent "the mathematically proven imminent dissolution of America from within." Glaser, on a CHD-hosted podcast, later recalled going "into court with 5,000 pages of fully vetted scientific materials, [and] perfect case presentation."
McGregor Scott, a U.S. attorney representing the presidential office, saw the group's work in a different light. Their complaint, he wrote, was "most accurately described as an unfocused, rambling anti-vaccine screed" culminating with "an implicit threat that, if the Court does not act, a military overthrow of the government might be in the offing."
Snopes reached out to Glaser about the group's legal effort. He responded with a series of false allegations about Snopes' supposed ties to the pharmaceutical industry. Despite multiple attempts, he did not directly answer any questions related to this story, requesting that we first provide him with, among other things, every advertisement displayed on Snopes "since 2020."
(Such a request is impossible because, like most websites, the programmatic ads Snopes displays are unique to each user's visit and largely outside the organization's control. Snopes discloses all financial information here).
Extreme claims that speakers made at SB 276 rallies, such as comparisons between vaccination and racial segregation, or the notion that vaccination was akin to a "mass, ongoing, human medical experiment," also appeared in The Control Group's court filing and oral arguments. The group repeatedly described vaccine requirements for public school children, government workers, and others as a form of unconstitutional discrimination similar to racial segregation.
"It used to be that in our nation we prevented people from going to school based on the color of their skin," Glaser argued in the group's district court appearance before U.S. Circuit Judge William Shubb on Feb. 22, 2021. "Now we're preventing them from going to school based on what's injected underneath their skin."
Shubb dismissed the case that day, agreeing with the presidential office that the president could not plausibly be considered liable for vaccine mandates, which are created and enforced by state governments. Also, Shubb wrote in his ruling, courts could not offer the type of relief the group sought.
The Control Group appealed the case's dismissal to the 9th U.S. Circuit Court of Appeals, alleging conflicts of interests with both Shubb and the judge from the 9th Circuit to whom the group was assigned. When the 9th Circuit nonetheless decided not to reconsider the case, the group asked the U.S. Supreme Court to hear its arguments.
In July 2022, the CHD, the anti-vaccine organization led by Kennedy, supported The Control Group by submitting an amicus brief to the Supreme Court. (Amicus briefs are legal filings made by outside parties with interest in a case.) In the brief, Mary Holland, then CHD's chief legal officer, repeated The Control Group's suggestion that the American populace was being experimented on. "Petitioners seek the Court's intervention to uphold their right to refuse participation in [...] the vast array of government-mandated vaccination requirements."
Ultimately, the Supreme Court declined to reconsider the appeal. That outcome, however, did nothing to stop the group from publicizing vaccines' alleged link to chronic illnesses. The study the group produced, advocates believed, would shake "the bedrock of medicine" by supposedly proving unvaccinated people are healthier and vaccines are the primary driver of chronic illness in America.
The Study: 'So You're Telling Me There's a Chance'
Using the survey responses from people who said they were unvaccinated, The Control Group's study was initially "published" as an exhibit in the group's complaint against the president. That report, titled "Statistical Evaluation of Health Outcomes in the Unvaccinated," is also available on the Children's Health Defense's website, among other places online.
Despite its name, the study didn't actually use a control group. TCG sought data only from completely unvaccinated individuals. A study using a control group would have recruited vaccinated people from the same locations and in the same way (online and in-person events) to compare their rate of chronic illness to the unvaccinated group. Instead, The Control Group merely looked to Centers for Disease Control and Prevention (CDC) estimates of chronic disease prevalence among Americans to see if survey respondents had fewer such illnesses in comparison:
A Control Group-produced chart used in litigation (thecontrolgroup.org)
The group collected data on 1,482 Americans. Within this pool of individuals, 88 (~6%) reported one chronic health condition, and 14 (less than 1%) reported two such conditions. In most (but not all) cases, The Control Group's comparisons considered children under the age of 18 separately from adults. Some 1,272 (86% of the respondents) were under the age of 18, leaving only 210 adults.
(The Control Group also collected data on whether a respondent's mother was vaccinated during her pregnancy and if a respondent had received a vitamin K-shot at birth.)
In legal filings, the group claimed its data provided absolute and unequivocal proof that vaccines cause chronic illness. Among other things, survey data supposedly demonstrated the "probability" that "excess health conditions seen in the vaccinated population under the age of 18 are not due to vaccine exposure is 1 in [84 sexvigintillion]."
This is a misrepresentation of basic statistical theory.
The "1 in 84 sexvigintillion" number — and other similarly extreme figures — were derived solely from calculations of the statistical significance between the number of chronic diseases in TCG's survey responses and CDC's averages. Such a calculation has no bearing on the validity of The Control Group's hypothesis that vaccines cause harm; it merely demonstrates the observed difference between the two groups (the CDC averages and survey respondents) is real.
In emails with Snopes, Garner demonstrated this misinterpretation of statistical significance on more than one occasion by citing the 1994 buddy comedy "Dumb and Dumber."
"The astronomical odds against the innocence of vaccines as the cause of this disparity," Garner told Snopes in an email, "gives absolute hilarity to the, 'So you're telling me there's a chance' [...] argument from the Dumb & Dumber movie, and all who dare to repeat it."
Erroneously claiming that statistical significance proves a specific hypothesis correct — an elementary mistake in the world of statistics — is the foundation of The Control Group's most sensational claims about chronic illness. There is, in fact, a clear difference between TCG respondents' incidence of chronic disease compared to America at large, but such a difference could well be a result of The Control Group's sampling of a population that differs from America's in ways unrelated to vaccines.
One potential explanation for the differences observed, for example, is that The Control Group targeted individuals of a higher-than-average, socio-economic class. This is relevant because, as the National Academies wrote in its 2019 report "A Roadmap to Reducing Child Poverty," for "almost every chronic condition, children from wealthier families experience better health."
Scholars generally recognize two forms of unvaccinated or under-vaccinated Americans, citing socioeconomic data: Those who are poor and lack access to vaccines, and those who are affluent yet under-vaccinated due to political or moral stances.
Speaking to Snopes by Zoom, Yale Professor of Biostatistics and Epidemiology Donna Speigelman said a study like the one The Control Group attempted to conduct would need to include unvaccinated individuals who are as identical as possible to the American population cited by the CDC, namely in terms of socioeconomic status, and other demographic details.
According to The Control Group, however, CDC research projects that consider such socioeconomic factors aim "to incite class and race wars" and benefit a "communist agenda." As a result, Garner said, her survey omitted questions about race, income, parental status, and other factors epidemiologists typically consider as relevant in such studies. "Only a moron goes looking for a non-biological cause," she told Snopes by email.
Another potential explanation for the better health outcomes in the The Control Group pool is that it targeted individuals who were abnormally healthy. The group's survey sought responses from people who were motivated to validate their choices to avoid vaccination and prove "the good health of their unvaccinated children." In legal filings, the group described ideal study participants for a proposed follow-up study as people who are "completely and extraordinarily healthy."
Yet another possible explanation for why Garner's survey respondents said they suffer from fewer chronic illnesses compared to CDC averages could be related to the fact that, as a whole, the group is far younger. The average survey participant was about 10 years old, based on raw data found on the group's website. The average age of the U.S. population, as of late 2022, was 38.8 years, according to the U.S. Census Bureau. Looking at The Control Group's 18-and-under group, children under 5 are overrepresented compared to the U.S. population, per Census estimates.
The likelihood of chronic disease increases with age. Many conditions the group investigated are classified as "age-associated" chronic diseases, including cancer, arthritis, diabetes, and cardiovascular disease. Diabetes can affect both children and adults, for example, but the disease disproportionately affects older people in the form of Type 2 diabetes. A risk factor for Type 2 diabetes, according to the CDC, is "being 45 or older." Among the 210 adults in The Control Group's survey, 18 were over the age of 45.
As a final defense of its methodologies, the group hid behind another specious statistical argument: It claimed that because it was able to sample such a large fraction of the (exceedingly small) unvaccinated American population, the survey's data must be representative of all unvaccinated people in the country from a mathematical standpoint.
Miguel Hernan, a professor of biostatistics and epidemiology at Harvard University's T.H. Chan School of Public Health, said that claim about sampling ratio was not true. "It isn't reasonable to argue that, because the population is small, any sampling is representative," he wrote via email.
The Control Group sampled far less than 1% of the American unvaccinated population, according to its own calculations. "Even if we could sample, say, 25% of a population, if the sampling is not random," Hernan said, "there is no guarantee that the 25% is expected to be representative in any sense."
Speigelmen, the Yale professor, agreed. "[The] idea that a large sample size makes bias go away? [...] That's completely wrong."
The Influencers: 'I'm Going To Blow Your Socks Off'
Under Kennedy's leadership, the Children's Health Defense enabled dissemination of The Control Group's misconstrued findings across a wide range of conspiracy and anti-vaccine media outlets. In other words, the Kennedy-run organization helped spread the misguided claim about vaccines being a primary driver of chronic illness in America to people who may not have heard it otherwise.
The Control Group's purported results have been shared by prolific anti-vaccine social media accounts, like Vigilant Fox, and anti-vax and conspiracy media outlets, like Natural News, The Exposé, and Age of Autism. Also, Garner has been interviewed at length by several anti-vaccine figures.
That virality followed promotion by the CHD, which publishes dubious vaccine information through its online publication, "The Defender." With this publication, Kennedy said in an October 2020 video announcing its launch, CHD would "weaponize information" by republishing "all the information that is censored everywhere else." Fittingly, The Defender's stories are often reposted in full on Alex Jones' conspiracy website, Infowars.
"The Defender" first published The Control Group's findings in a January 2021 story authored by TCG attorney Glaser. The report claimed, in part, "America is dying from the current trajectory of chronic illness" and that "our Control Group pilot survey proved it is the vaccines causing our nation's demise." People in CHD's orbit of influencers ran with that finding.
Paul Thomas, a former pediatrician, was among that group. He had made a name for himself by alleging that the CDC's recommended childhood vaccination schedule was harmful. In October 2022, the state of Oregon forced him to surrender his medical license, in part, because the state said he was discouraging parents from vaccinating their children. He hosts a weekly podcast produced by CHD.
Thomas used that CHD podcast to promote the The Control Group's effort on several occasions. On a January 2022 appearance on Thomas' podcast, for instance, Glaser explained the purported benefits of the group's scientific work. "If you want to show that vaccines are the healthiest thing on the planet, you need a control group. If you want to show they're harming society, you need a control group," he said. "There's no substitute for this."
Thomas was impressed. A few months later, Thomas used The Control Group's data as a key reveal in a talk distributed to online participants of a so-called "health freedom conference" — that is, a collection of videos promoting, among other things, unsubstantiated claims about supplements and vaccines. "I'm going to blow your socks off," he said before diving into the group's data.
A clip of that talk went viral online — both at the time of the conference and at subsequent times — pushing its information beyond CHD circles. Believers of the data regularly share a portion of the talk with copy-and-pasted text, beginning, "Dr. Paul Thomas Blows Up The Conventional Vaccine Narrative With Stunning Data":
"Wouldn't it be nice if you had known that, [by] not vaccinating, you wouldn't have had to deal with [diabetes]?" Thomas asked in the clip. He did not say that assertion was based on survey responses from a group of individuals including only 18 people over the age of 45, the age at which the CDC says the risk for Type 2 diabetes really takes effect.
The Control Group's work also caught the attention of entrepreneur Steve Kirsch — a frequent speaker alongside Kennedy at rallies and podcasts on issues surrounding vaccines and online censorship. An inventor of the optical mouse in the 1990s, Kirsch became one of the U.S.'s loudest and most persistent anti-vaccine voices during the COVID-19 pandemic.
In June 2023, Kirsch testified before the Pennsylvania State Senate as part of a panel that discussed "medical freedom" — a term often embraced by anti-vaccine advocates to describe their movement. His presentation cited The Control Group's study.
"[The study has] over a thousand people who are unvaccinated," Kirsch told the committee in a video that regularly goes viral, repeating The Control Group's talking point alleging that virtually no unvaccinated people have chronic disease compared to 60% of vaccinated individuals. Like Thomas, Kirsch did not elaborate on evidence supporting the former figure — that it was derived from a pool of 210 adults with an average age of 30.
Jonathan Jarry, a science communicator at McGill University in Montreal, Quebec, wrote in a profile of Kirsch that his "answer to his opponents is straight out of the quack handbook: debate me, bro!" He often uses Control Group data in such debates. Kirsch did not respond to a list of questions for this Snopes report, after he previously challenged this reporter to a debate against a panel of "autism experts," including Garner, The Control Group's leader.
In August 2023, four months after launching his campaign for president, Kennedy explicitly gave The Control Group's work a seal of approval by including it in his book, "Vax-Unvax: Let The Science Speak." Co-authored by CHD scientific officer Brian Hooker, the book purports to be an exhaustive collection of scientific evidence demonstrating that vaccinated children are more likely to be diagnosed with a wide range of chronic health conditions.
"The Control Group study [...] demonstrates that vaccinated children have a much higher incidence of specific chronic disorders than unvaccinated children," Kennedy and Hooker wrote. "Most notably," they claimed, referring to specific comparisons found in The Control Group study, "the vaccinated have a twenty times higher incidence of ADHD than the unvaccinated and over a ten times higher incidence of autism than the unvaccinated."
(Gab / Children's Health Defense)
In adversarial interviews with people who challenge his views on vaccines, Kennedy has repeatedly asserted there "are hundreds and hundreds'' of studies demonstrating harm from vaccines, without going into details. "Vax-Unvax" — which, according to its publisher, is a collection of just over 100 such studies, provides a look not only at the quality of scientific work underlying such platitudes but also provides context for statements by Kennedy about his scientific literacy. For instance, on Joe Rogan's podcast in June 2023, he claimed he is "comfortable with reading science" and knows "how to read it critically."
Hooker responded to some of Snopes' questions about "Vax-Unvax" on Kennedy's behalf. Hooker said Snopes' argument about the age of Control Group respondents (that their youth compared to the actual American population could drive the difference in health outcomes) was "obviated" because he and Kennedy only looked at data concerning children. "We are not affirming the entirety of Garner's study," he told Snopes, "but featuring the information we feel is most scientifically valid."
Notably, Hooker falsely argued The Control Group's methodology — that is, that it did not correct for the overrepresentation of young people and ignored socioeconomic factors — was in line with CDC-authored studies. Hooker provided Snopes with three studies as purported examples, but, contrary to Hooker's assertions, each of those studies used control groups, corrected for age, and/or accounted for socioeconomic factors. Hooker did not respond to a follow-up email asking for clarification.
The Control Group's inclusion in "Vax-Unvax" was far from the only example of Kennedy's flawed interpretation of statistics to justify his rhetoric. The same chapter featuring the group — "Health Outcomes Associated With The Vaccine Schedule" — included two infamously poor studies covered by Snopes in the past. Three of the eight studies in the chapter were authored by Hooker or ex-pediatrician Paul Thomas.
In September 2023, after an aggressive push by the Children's Health Defense and Kennedy to promote the book, it hit the New York Times' bestseller list.
The Campaign: 'A Tsunami of Chronic Disease in Our Country'
Despite telling numerous pundits he is "not leading" on the issue of vaccines during his presidential bid, Kennedy's history of activism has prompted some pundits and journalists to question if that's true, considering the fact he's brought up vaccines, both implicitly and explicitly, while campaigning. For instance, when Kennedy initially announced his presidential campaign in April 2023, running as a Democrat, he vowed to reduce chronic disease in children if elected president.
"If I haven't significantly dropped the level of chronic disease in our children by the end of my first term," he said, "I do not want you to reelect me." He did not say how he would accomplish such a goal. In other settings, however, he explicitly blamed chronic illnesses on vaccines. In June 2023, for example, Kennedy told Wall Street Journal columnist Gerard Baker, "[The] science is overwhelming and very clear that, yes, the vaccines are producing a tsunami of chronic disease in our country."
Numerous CHD staff members or anti-vaccine activists presently work for Kennedy's campaign, further evidence that anti-vaccine advocacy is part of his presidential bid. They include Mary Holland, the former chief legal officer and president of CHD who authored the amicus brief to the Supreme Court in support of The Control Group; Stefanie Spear, who edited CHD's online content, including "The Defender"; and Del Bigtree, an activist who organized the April 10, 2019, rally that apparently inspired Garner's work.
Also, some notable supporters of his campaign have ties to the anti-vaccine movement and the promotion of The Control Group's work. For instance, the pro-Kennedy super PAC American Values 2024, which paid $7 million for a Kennedy campaign ad during the 2024 Super Bowl, was co-founded by Tony Lyons — the head of a publishing company that prints most books authored by Kennedy and CHD staff, including "Vax-Unvax." Kirsch, who provided funds to American Values early on, according to FEC filings, was until recently listed on the PAC's website for the group as a "surrogate" — presumably someone who advanced its talking points to the media.
In sum, Kennedy's embrace of The Control Group's data — data potentially inspired by his own words — highlights the ability of misinformation to be a self-sustaining phenomenon. Public-health advocates worry Kennedy's presidential campaign could lend new exposure and credibility to his claims regardless of their factualness, resulting in greater public misconceptions about vaccines.