ASSAULT ON SCIENCEWhy a Study Claiming Vaccines Cause Chronic Illness Is Severely Flawed – a Biostatistician Explains the Biases and Unsupported Conclusions
At a Senate hearing on Sept. 9, 2025, witnesses supporting HHS Secretary Robert F. Kennedy Jr.’s campaign against vaccination, presented an unpublished study, claiming the study was never published because the authors feared being fired for finding evidence supporting the health risks of vaccines. This claim was false. The study has serious design problems that keep it from revealing much about whether vaccines affect children’s long-term health.
At a Senate hearing on Sept. 9, 2025, on the corruption of science, witnesses presented an unpublished study that made a big assertion.
They claimed that the study, soon to be featured in a highly publicized film called “An Inconvenient Study,” expected out in early October 2025, provides landmark evidence that vaccines raise the risk of chronic diseases in childhood.
The study was conducted in 2020 by researchers at Henry Ford Health, a health care network in Detroit and southeast Michigan. Before the Sept. 9 hearing the study was not publicly available, but it became part of the public record after the hearing and is now posted on the Senate committee website.
At the hearing, Aaron Siri, a lawyer who specializes in vaccine lawsuits and acts as a legal adviser to Secretary of Health and Human Services Robert F. Kennedy Jr., said the study was never published because the authors feared being fired for finding evidence supporting the health risks of vaccines. His rhetoric made the study sound definitive.
As the head of biostatistics at the University of Pennsylvania’s Perelman School of Medicine, when I encounter new scientific claims, I always start with the question “Could this be true?” Then, I evaluate the evidence.
I can say definitively that the study by Henry Ford Health researchers has serious design problems that keep it from revealing much about whether vaccines affect children’s long-term health. In fact, a spokesperson at Henry Ford Health told journalists seeking comment on the study that it “was not published because it did not meet the rigorous scientific standards we demand as a premier medical research institution.”
The study’s weaknesses illustrate several key principles of biostatistics.
Study Participants and Conclusions
The researchers examined the medical records of about 18,500 children born between 2000 and 2016 within the Henry Ford Health network. According to the records, roughly 16,500 children had received at least one vaccine and about 2,000 were completely unvaccinated.
The authors compared the two groups on a wide set of outcomes. These included conditions that affect the immune system, such as asthma, allergies and autoimmune disorders. They also included neurodevelopmental outcomes such as attention-deficit/hyperactivity disorder, or ADHD, autism and speech and seizure disorders, as well as learning, intellectual, behavioral and motor disabilities.
