Misleading: The studies cited in the CHD interview with Brian Hooker contain significant methodological flaws that render the findings unreliable and biased. No mention of these flaws were made during the interview, nor the fact that two studies were retracted.
FULL CLAIM: “The more vaccinated a child is, the more they have what's called innate immune suppression”; “Vaccinated kids [are] more likely to have chronic disease”; “Vaccinated kids [are] 20 times more likely to have ADHD”; “Vaccinated children are more likely to visit a doctor than unvaccinated children for” conjunctivitis, anemia, ear infections, respiratory infections, etc.
REVIEW
On 7 July 2023, the anti-vaccine organization Children’s Health Defense (CHD) published a video of an interview with chemical engineer Brian Hooker, offering a sneak peek into Hooker’s upcoming book “Vax-Unvax: Let the Science Speak”, due to be published in August 2023.
According to a description of the book as listed on Amazon, the book discusses “The Studies The CDC Refuses To Do”, stating that “Given the massive push to vaccinate the entire global population, this book is timely and necessary for individuals to make informed choices for themselves and their families”.
Brief segments of the interview were posted by CHD on Twitter (see here, here, here, here, and here). All segments show how vaccinated children are purportedly more likely to develop or be diagnosed with various medical conditions, including autism and infections, compared to unvaccinated children.
In light of Hooker’s previous false claims about vaccines and his affiliation with CHD, the gist of these posts—and by extension the book—is clear: that unvaccinated children are healthier than their vaccinated counterparts and that vaccination is detrimental to children’s health.
However, the studies cited by Hooker in the interview contain significant methodological flaws, which other scientists have criticized before. Some of this criticism was covered in previous Health Feedback reviews. Two of the studies have been retracted for failing to provide sufficient evidence for their conclusions, but this wasn’t mentioned during the CHD interview.
This review will discuss the methodological flaws in the studies and why they don’t provide reliable evidence for the claim that unvaccinated children are healthier than vaccinated children. It will also show that better-designed studies have found no evidence that vaccinated children are more likely to have poorer health outcomes compared to unvaccinated children.
Contents
- Twice-retracted study by Mawson et al. relied on a survey of homeschooling parents, not representative of the general population
- Vaccines don’t weaken children’s immune system
- CDC study unable to establish a causal relationship between aluminum levels in vaccines and asthma
- Now-retracted study by Lyons-Weiler and Thomas relied on a new, unvalidated metric to suggest vaccinated children are more likely to be sick
- Well-designed studies didn’t find an increased risk of poorer health in vaccinated children compared to unvaccinated children
- Conclusion
- Scientists’ feedback
- On other common vaccine-related claims
- References
Twice-retracted study by Mawson et al. relied on a survey of homeschooling parents, not representative of the general population
One of the studies that made an appearance in the interview was led by Anthony Mawson, a public health scientist who voiced support for Andrew Wakefield, the former physician who published a now-retracted study associating autism with the MMR vaccine. Wakefield’s study was later found to contain critical flaws, including data fabrication. In a letter, Mawson wrote of Wakefield’s study as being “truly remarkable, well written and brilliantly documented”.
Mawson’s study, which was crowdfunded by two anti-vaccine organizations Generation Rescue and Children’s Medical Safety Research Institute, performed a survey of mothers of homeschooled children, asking about their children’s vaccinations and medical history. This was facilitated through a partnership with the National Home Education Research Institute. On top of this, “A number of homeschool mothers volunteered to assist NHERI promote the study [sic] to their wide circles of homeschool contacts”.
Based on the survey responses, Mawson et al. concluded that vaccinated children were significantly more likely than the unvaccinated to have been diagnosed with allergic rhinitis (30 times more likely); other allergies (3.9 times more likely); eczema/atopic dermatitis (2.9 times more likely); a learning disability (5.2 times more likely), ADHD (4.2 times more likely), ASD (4.2 times more likely); any neurodevelopmental disorder (3.7 times more likely).
However, the method of collecting information in the study results in several critical biases. David Gorski, a cancer surgeon and editor of Science-Based Medicine, wrote about the study in this article for Science-Based Medicine.
He pointed out that homeschooled children don’t represent the general population and that homeschooling tends to also be associated with anti-vaccine views. This is evidenced in the study population, in which more than a third of children were unvaccinated. This is in contrast to national statistics of vaccine coverage: only 1.3% of children born in the U.S. between 2016 and 2017 remained completely unvaccinated at two years of age[1].
Mawson et al. also didn’t attempt to independently verify that the survey responses were accurate, such as by examining the children’s medical records.
Furthermore, the health-seeking behavior of parents who vaccinate their children is likely different from parents who don’t, for various reasons, including a greater trust in medical professionals and socioeconomic differences[2,3].
Parents of vaccinated children “tend to take their children to visit the doctor more regularly, which means that health disorders their children have are more likely to be diagnosed and treated. They’re also less likely to be seeing naturopaths and other alternative practitioners,” Gorski pointed out.
This would influence how often vaccinated children are diagnosed with medical conditions relative to unvaccinated children. What the study is unable to show is that vaccinated children develop these conditions more often. But the interview didn’t make this distinction clear nor did it warn viewers of the study’s caveats.
Vaccines don’t weaken children’s immune system
In another segment, Hooker claimed that “The more vaccinated a child is, the more they have what’s called innate immune suppression”.
There’s no evidence that childhood vaccination weakens the immune system. On the contrary, they strengthen a child’s immune defenses against vaccine-preventable diseases, many of which were once common childhood illnesses. This is supported by the findings of a study in Denmark, which included more than 800,000 children. The researchers found no statistically significant adverse association between receiving routine childhood vaccinations and hospitalization due to infectious diseases[4].
Hooker supported his claim by citing two studies that he co-authored with journalist Neil Miller. One of the two studies was discussed in a previous Health Feedback review.
In that study, Hooker and Miller looked at medical records containing diagnoses of developmental delay, asthma, ear infection, and gastrointestinal disorder. The records came from three pediatric practices in the U.S., but no information was given as to how these practices were selected.
By comparing the number of vaccinated children who had received any of the four diagnoses to that of unvaccinated children, the authors concluded that vaccination is associated with a greater incidence of such diagnoses.
But scientists who evaluated the study told Health Feedback that the study contained numerous methodological flaws that make its findings biased and unreliable. [Click to see scientists’ full comments on this study.]
Karina Top, an associate professor of pediatrics at Dalhousie University who studies vaccine safety, noted that 30% of the children in the study had received no vaccines. This contrasts with national statistics showing that only 1.3% of U.S. children at two years of age remained completely unvaccinated[1].
For Top, this raised a “red flag” about the type of practice included in the study. “Were the physicians not supportive of vaccines or willing to give medical exemptions and therefore attracted families that were more hesitant around vaccines or who had objections to vaccines for religious, cultural or other reasons?” she questioned.
Abram Wagner, a research assistant professor of epidemiology at the University of Michigan, highlighted the fact that the study didn’t control for differences between the groups of unvaccinated and vaccinated children, which could have affected the outcomes being examined in the study.
“We know vaccinated and unvaccinated children can come from different environments: living in rural (vs. urban) areas, wealth, proclivity to go to the doctor, etc. All these factors could differ between vaccinated and unvaccinated children and could explain differences in health outcomes,” he explained.
In short, while the study found that vaccinated children were more likely to receive diagnoses of developmental delay, asthma, ear infection, and gastrointestinal disorder, what it didn’t show was that such conditions arise more often in vaccinated children. The higher frequency of diagnoses could be due to differences in health-seeking behavior that are unrelated to vaccination.
The other Hooker and Miller study, which was published in 2021, surveyed parents of children from three pediatric practices in the U.S. to obtain information about vaccination and diagnoses. It is unknown if these are the same practices involved in the 2020 study.
It harbors some of the same problems also present in their 2020 study. For instance, about 60% of the study cohort were completely unvaccinated, indicating that the study population isn’t representative of the general population. It points to a significant bias in the way the study population was sampled.
Again, Hooker and Miller provided no information about how the pediatric practices included in the study were selected, thus it is challenging to understand how the bias came about. The difference in health-seeking behavior between parents who vaccinate their children and parents who don’t is also again unaccounted for.
CDC study unable to establish a causal relationship between aluminum levels in vaccines and asthma
Another study cited by Hooker during the interview was performed by scientists at the Kaiser Permanente Colorado Institute for Health Research and the CDC. which supposedly showed that “Vaxxed Kids [Are] More Likely To Have Eczema + More”.
Using data from the Vaccine Safety Datalink, a database established by the CDC, the scientists looked at whether vaccine-related aluminum exposure in children’s first two years of life was associated with the likelihood of developing asthma in the next three years of life[5]. Aluminum is present in childhood vaccines in the form of aluminum salts. They act as adjuvants, which enhance the immune system’s response to vaccination.
More than 300,000 children were included in the study. Based on their analysis, the authors reported that vaccine-related aluminum was positively associated with the likelihood of developing persistent asthma later in childhood.
Much is made of this association in the CHD interview, but it didn’t tell viewers about important caveats regarding the study, which the authors acknowledged. These caveats were discussed in a 2022 article by the Vaccine Education Center (VEC) at the Children’s Hospital of Philadelphia.
One of the caveats relates to the study’s attempt to associate vaccine-related aluminum in the first two years of life with the risk of asthma in the years after. This is because aluminum is also present in food and water, not only in vaccines. So only measuring aluminum levels in vaccines doesn’t provide a complete picture of aluminum exposure. The VEC gave this analogy:
“This is like saying that the ice cream you consumed in elementary school is associated with your weight gain in middle school. It’s problematic because so many other things, including ice cream you ate while in middle school, would also affect your weight.”
Another reason is because aluminum is eliminated from the body over time, raising the question of how aluminum in vaccines given in the first two years of life would influence a disease that developed a few years afterwards. The VEC:
“Once aluminum reaches the bloodstream, most of it (90%) is bound to a protein, called transferrin, and removed through our kidneys. About half is eliminated within 24 hours and about three-fourths, within two weeks. As such, aluminum exposure in the first two years of life would be difficult to associate with the development of a disease in the third to fifth year of life—a time when most of the aluminum from the vaccines is long gone.”
Aluminum levels in the body also change depending on the chemical environment, not just the amount of aluminum is food and drink:
“For example, if you eat an orange at lunch with your turkey and cheese sandwich, you are likely to absorb more aluminum from the cheese and bread in your sandwich than if you eat a banana with your sandwich. Does this mean you should not have that orange? Of course, not. We consume milligrams of aluminum every day and only a small portion of that aluminum makes it out of our digestive tract and into our body.”
In brief, the researchers were unable to account for aluminum exposure and variability in processing through food and drink. Furthermore, they also didn’t account for environmental pollutants or a family history of asthma or allergies, even though these variables also influence aluminum exposure and asthma risk.
Ultimately, there are several reasons why the study’s findings should give us pause and why it doesn’t prove that aluminum in vaccines causes asthma or other inflammatory conditions. The mere fact that an association exists doesn’t constitute sufficient evidence of a causal relationship. These caveats were, again, unacknowledged by Hooker.
Now-retracted study by Lyons-Weiler and Thomas relied on a new, unvalidated metric to suggest vaccinated children are more likely to be sick
Finally, Hooker cited a study by bioinformatician James Lyons-Weiler and pediatrician Paul Thomas,. Lyons-Weiler has promoted vaccine misinformation, while Thomas believes vaccines cause autism. Thomas has promoted an alternative vaccine schedule that delays vaccination on the pretext that this limits exposure to toxins in vaccines.
This is despite the fact that no ingredient in childhood vaccines is present in toxic amounts, experts told Health Feedback previously. And there isn’t evidence supporting the belief that there are benefits to delaying vaccines—what this accomplishes is to unnecessarily expose a child to preventable infections.
The study was published in the International Journal of Environmental Research and Public Health in November 2020. It was retracted by the journal in July 2021, after an investigation found that “the conclusions are not supported by strong scientific data”.
The study, too, was previously discussed in a 2020 Health Feedback review that predated the retraction by several months.
In the study, the authors examined the billing and medical records of more than 3,000 patients at Thomas’ clinic. They created a metric for the study, called Relative Incidence of Office Visits, to measure disease burden in unvaccinated and vaccinated children.
Gorski wrote about this study in an article on his blog Respectful Insolence, pointing out multiple problems with this approach:
“The authors claim that RIOV ‘reflects the total number of billed office visits per condition per group, reflecting the total disease burden on the group and the population that it represents,’ but no good analysis or references are provided to show that RIOV does, in fact, correlate with disease burden, particularly when using billing data […] If the primary outcome is a new, unvalidated metric, it is incumbent upon the investigator to demonstrate its robustness.”
Another pertinent issue is the possibility that Thomas’ own views on vaccines affect the way that his practice approaches diagnoses of autism. Gorski:
“Dr. Thomas believes that vaccines cause autism. That right there introduces unconscious bias that could affect how likely he and his staff are to investigate subtle signs of autism and [to refer out] for evaluation based on vaccination status and how likely he is to ascribe various diagnoses to ‘unvaxxed’ children compared to ‘vaxxed’ children. One can easily imagine this bias leading to unvaccinated children to be less likely to be given an autism diagnosis than vaccinated children or to be—dare I say?—brought into the office as often for various conditions that Dr. Thomas attributes to vaccines.”
To summarize: the analyses conducted in the study are based on a new, unvalidated metric developed by the authors. They did not provide evidence showing it is a reliable indicator of disease incidence. In addition, potential bias owing to the authors’ personal views on vaccines may also have affected the way illnesses were diagnosed in unvaccinated and vaccinated children, which wasn’t addressed in the study. Once again, the weaknesses in this study were glossed over during the CHD interview.
Well-designed studies didn’t find an increased risk of poorer health in vaccinated children compared to unvaccinated children
There are several published studies comparing health outcomes of vaccinated and unvaccinated children that are better-designed than those cited by Hooker. These show that vaccinated children aren’t more likely to develop medical conditions than unvaccinated children.
These studies, which contradict Hooker’s views, were unmentioned during the interview.
A 2004 study in Pediatrics showed no association between vaccines and developmental delay[6]. Another study found that children who had been vaccinated in the first year of life actually performed better on cognitive tests[7]. Similarly, measles vaccination in developing countries, specifically Ethiopia, India, and Vietnam, was associated with better cognitive test scores[8].
A 2011 study in Germany, which examined the incidence of allergies and infections among more than 13,000 individuals, did not find adverse health outcomes associated with vaccination[9]. Another study in Germany, published in 2014, examined more than 1,300 individuals and found that vaccination was associated with a significantly lower incidence of asthma[10].
A 2020 Cochrane Review of 138 studies showed no evidence supporting an association of MMR vaccination with asthma, bacterial or viral infections, cognitive delay, type 1 diabetes, dermatitis/eczema, and hay fever[11]. At least 20 studies have shown that vaccines are not associated with autism[6,12-31].
The U.S. Institute of Medicine concluded in a 2013 review that the childhood immunization schedule is safe[13]. The VEC at the Children’s Hospital of Philadelphia has summarized the scientific evidence showing that vaccines are not associated with a higher risk of asthma or allergies and neurodevelopmental problems like attention deficit/hyperactivity disorder. The American Academy of Pediatricians (AAP) has also compiled a list of studies relevant to vaccine safety here.
Conclusion
The CHD interview promoting Hooker’s upcoming book, which purports to “Let The Science Speak”, cited multiple studies suggesting that scientific evidence shows vaccinated children to be less healthy than unvaccinated children.
In truth, while the studies Hooker cited in the video produced results that appear to support this impression—at least on the surface—the studies were performed in a heavily flawed manner that introduced significant bias. The interview didn’t acknowledge that these important limitations were present.
The criticism regarding these studies has been available long before the CHD interview and Hooker’s book, some of it for years, but no mention of such criticism was made during the interview. Nor did the interview mention that two of the studies had been retracted for failing to provide sufficient evidence to support their conclusions.
Ultimately, the interview provides a one-sided view of the scientific studies on this subject and misleads viewers into thinking that these studies constitute credible scientific evidence for the claim that unvaccinated children are healthier than vaccinated children.
Better-designed studies—which were never discussed in the interview—have found no evidence that vaccinated children have poorer health compared to unvaccinated children. The AAP recommends on-time routine immunization of all children and adolescents according to the CDC’s Recommended Child and Adolescent Immunization Schedule.
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SCIENTISTS’ FEEDBACK
[The following comments come from the evaluation of a related claim related to the 2020 study by Hooker and Miller.]
Karina Top, Associate Professor (Division of Pediatrics), Dalhousie University:
First, we know that the large majority of parents do choose to follow vaccine recommendations and at age two only 1.3% of U.S. children had received NO vaccinations. The finding that 30% of children in their sample of three pediatric practices had received no vaccines raises a red flag about the type of practice/physician and patients in their practice. Were the physicians not supportive of vaccines or willing to give medical exemptions and therefore attracted families that were more hesitant around vaccines or who had objections to vaccines for religious, cultural or other reasons? No details are provided regarding how they chose the practices, their location, or type of insurance they accepted (e.g. private, Medicaid).
Because the large majority of children are vaccinated, we know that unvaccinated children are very different from vaccinated children in ways that may also alter their likelihood of being diagnosed with childhood conditions such as asthma, ear infections, and development delay. For example, children from large families with low socioeconomic status may have difficulty getting to vaccination appointments, but those same challenges may make it difficult to get to a physician appointment for a new health problem. The analysis did not take into account demographic or other factors that might influence both a child’s chance of getting vaccinated and their chance of getting diagnosed with any of those conditions (e.g. insurance status, parent age, education, race/ethnicity, presence of other children).
Finally, both authors are well known for promoting unscientific claims about potential harms of vaccines, including the myth of an association between vaccines and autism for which the lead author has had two of his publications retracted by journals, suggesting an inherent bias in their approach.
Abram L. Wagner, Research Assistant Professor (Epidemiology), School of Public Health, University of Michigan:
Vaccines are safe and effective. Unvaccinated children can get terrible diseases—an unvaccinated 6-year old boy in Oregon was diagnosed with tetanus after having uncontrollable muscle spasms and he was hospitalized for 8 weeks. The Hib vaccine protects against epiglottitis—the swelling of the throat which can cause infants to suffocate. The whooping cough vaccine protects against a disease where children can cough until they throw up and break their ribs.
A recent study examined the relationship between the number of vaccines administered and different health outcomes. A large problem with this study is that the researchers did not control for differences between the groups of unvaccinated and vaccinated children. We know vaccinated and unvaccinated children can come from different environments: living in rural (vs. urban) areas, wealth, proclivity to go to the doctor, etc. All these factors could differ between vaccinated and unvaccinated children and could explain differences in health outcomes. Additionally, this study includes children from handpicked medical practices and is not representative of the general population.
The first author’s previous publication was retracted for fraudulent methods and undisclosed conflicts of interest.
Nina Masters, PhD Student (Epidemiology), University of Michigan:
[Note: Masters’ title and affiliation listed above reflect the ones at the time of the earlier evaluation. She is presently an epidemiologist at the CDC.]
This analysis does not account for differential healthcare seeking between the vaccinated and unvaccinated. The authors do not evaluate whether there are different numbers of doctor’s visits between the two groups. For example, the unvaccinated group could be more likely to miss appointments with their doctor, which could lead to them receiving fewer vaccines and also having less opportunity for doctor’s visits in which to be diagnosed with various health conditions.
The authors even acknowledge that this bias may exist: “A single significant relationship was seen for the head injury control diagnosis at the 18-month vaccination cut-off, which may be indicative of differences in healthcare-seeking behavior among families of vaccinated versus unvaccinated children.” Yet they do not present any information that would enable the reader to better understand the role and scale of this bias.
Diagnosis with many developmental delays may occur in the 3-5 year range, but growing evidence has shown that the factors that lead to these diagnoses occur early in life and during prenatal development—long before any vaccination.
READ MORE
Health Feedback has also addressed other common claims regarding vaccines and their effect on health. More information can be found in the following articles:
REFERENCES
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