By Tomas Fürst at Brownstone dot org.

Note - this article was coauthored with Vibeke Manniche, MD, PhD.

Few issues of contemporary science are more contentious than the relation between childhood vaccines and adverse health outcomes. So, whenever a new study appears, it attracts a lot of attention. See the new study by Andersson et al., titled Aluminum-adsorbed vaccines and chronic diseases in childhood. A nationwide cohort study appeared in the Annals of Internal Medicine in July 2025.

Conclusion: "Cumulative aluminum exposure from vaccination during the first 2 years of life was not associated with increased rates of any of the 50 disorders assessed."

We went through the paper, left no stone unturned, and report that we do not like what we found:

1. First, there is the issue of the "evolving" supplement. The original supplement included data on 2,239 neurodevelopmental events (such as autism and ADHD), but it is no longer accessible. It has been replaced by a revised version that now reports 5,200 neurodevelopmental events (see Table 11 of the Supplement).

This increase in the number of events altered the confidence intervals, and the updated data now show a statistically significant association between certain neurodevelopmental outcomes - particularly autism and ADHD - and aluminum exposure from vaccines.

This finding directly contradicts the paper's conclusion, which states: "Cumulative aluminum exposure from vaccination during the first 2 years of life was not associated with increased rates of any of the 50 disorders assessed." (See also the article at Children's Health Defense)

2. The study suffers from a major limitation due to its short follow-up period. In Denmark, children are typically diagnosed with autism, autism spectrum disorders, and ADHD between the ages of 7 and 12 - or even later, depending on the severity of symptoms. However, the authors only tracked the children up to age 5, virtually ensuring that many relevant outcomes were missed.

Therefore, even if the study had not found an association between aluminum exposure and adverse neurodevelopmental outcomes (which, in fact, it had - see point 1), the authors still would not have been in a position to conclude that no such association exists. Nevertheless, the corresponding author, Anders Hviid, publicly misrepresented the findings, claiming that the study showed there was no link between aluminum exposure and autism or ADHD.

It is also important to notice that SSI (the institution behind the study) has great economic interests in developing and selling vaccines.

3. The exclusion criteria are suspect: "To be included in our study, children needed to be alive at age 2 years, not have emigrated from Denmark, not have been diagnosed with certain congenital or preexisting conditions (including congenital rubella syndrome, respiratory conditions, primary immune deficiency, and heart or liver failure)." However, death may be linked to vaccination. Moreover, many of the listed "preexisting" conditions may be, in fact, adverse events of previous vaccines.

Thus, if the authors exclude many children who had been harmed by vaccines, they may miss some effects entirely. We would like to see the analysis with no children excluded.

4. Adjusting for the number of office visits (pre 2 years of age) may mask the effect significantly. Office visits are a "proxy" for the outcome (children who end up with some diagnosis probably visited GPs more often). Thus, there is a risk that the effect will be "adjusted away." To give an example, if we want to measure the effect of an intervention on blood flow through the left arm, we should not adjust for blood flow in the right arm.

These two quantities are very probably correlated and adjusting for one will probably adjust much of the effect away.

5. According to Figure 1, more than 34,000 children were excluded because they had implausibly many registered vaccines in the first 2 years of life. Why would that be? This casts seriou...