US health secretary and vaccine sceptic Robert F. Kennedy Jr has called for the retraction of a Danish study that found no link between aluminium in vaccines and chronic diseases in children — a rare move for a US public official. Aluminium has been used for almost a century to enhance the immune system’s response to some vaccines. But some people claim the ingredient is linked to rising rates of childhood disorders such as autism.

Public-health officials in Kennedy’s position rarely request that studies be retracted, says Ivan Oransky, a specialist in academic publishing and co-founder of the media organization Retraction Watch. Through this request, “Secretary Kennedy has demonstrated that he wants the scientific literature to bend to his will”, says Oransky.

The study in question, published in Annals of Internal Medicine in July, is one of the largest of its kind, looking at 1.2 million children born over more than two decades in Denmark. The authors reported that no significant risk of developing autoimmune, allergic or neurodevelopmental disorders was associated with exposure to aluminium compounds in vaccines.

In an opinion piece published on TrialSite News on 1 August, Kennedy called into question the study’s methodology, analysis and results. Since his appointment as head of the US Department of Health and Human Services, Kennedy has bypassed normal scientific review processes to change vaccine recommendations and terminated grants for projects on mRNA vaccines.