By Peter C. Gøtzsche at Brownstone dot org.

The US childhood vaccination programme is huge, 68 vaccine doses targeting 18 different diseases versus only 17 vaccine doses for 10 diseases in Denmark.

It is unknown if the net effect of so many vaccinations is beneficial, and in August 2025, two physicians launched a federal lawsuit against the Centers for Disease Control and Prevention (CDC) for failing to study the cumulative effects of its childhood vaccine schedule. They noted that "America administers more vaccines than any nation on earth while producing the sickest children in the developed world."

Two researchers who have compared countries found a dose-response relationship: Nations that require more vaccines for their infants had higher infant mortality, neonatal mortality, and under age five mortality.

Paediatric chronic disease prevalence in the US has risen to nearly 30% in the last 20 years, and vaccination schedules are among the possible causal factors that Robert F. Kennedy, Jr., Secretary of Health and Human Services, has declared he will investigate. A CDC workgroup will examine if there are any differences in efficacy or safety between the US and Danish schedules. They will also look at the the timing, order, and ingredients, e.g. the amount of aluminium, which is pertinent, as aluminium in vaccines is harmful.

I am aware of only one study in the whole world that used birth cohorts and compared the occurrence of chronic diseases in a vaccinated group with that in an unvaccinated group and that took account of confounders. It was carried out at the Henry Ford Health System in Detroit but was never published because the researchers were warned that it could cost them their jobs. The study was completed in 2020, and its results came to light on 9 September 2025 because it was introduced into the Congressional Record during a Senate hearing on "The Corruption of Science."

For over two decades, the Institute of Medicine had urged the CDC to conduct such a study using its Vaccine Safety Datalink, but the CDC never did.

A ground rule in evidence-based medicine is that we should use the best available evidence when we make decisions. As the Henry Ford study is the only one that compared unvaccinated with vaccinated kids for development of chronic diseases and that took account of confounders, it is very important that we examine this study carefully for its validity.

The Henry Ford Study

When I read the unpublished manuscript, I found that it was above average quality. The authors were genuinely surprised by their results and did sensitivity analyses to test their robustness. They provided a very interesting discussion about issues that might explain their findings, which they put in context. As they had expected to find that vaccination reduces the risk of developing chronic diseases, I see them as being more pro-vaccine than anti-vaccine. For example, they wrote in the Introduction:

"Common parental concerns relate to the growth of the vaccine schedule, administering multiple vaccines contemporaneously, and the potential for long-term adverse health outcomes from vaccination. Research addressing these vaccine safety concerns can assist clinicians in discussions with their patients and serve to reassure parents of the overall safety of vaccination…Addressing this significant data gap could allay parental concerns and bolster vaccine confidence."

A professor of biostatistics from Pennsylvania, Jeffrey S. Morris, often comments on my tweets about vaccines, and he provided several interesting comments about the study related to my tweets about it. I therefore contacted him and we corresponded about the issues.

Morris and I agree that scientific debate is vital for the progress of science, and I hope that an account of our differing views about the study will be of interest.

The primary outcome of the study was a chronic health composite outcome which included conditions identified by the Child and Adolescent Health Me...