Kennedy – a vaccine sceptic – has long raised concerns about a rise of autism, but it is unclear whether the health department will blame inoculations in its forthcoming report.
“By September we will know what has caused the autism epidemic,” the health secretary said at a spring cabinet meeting with President Donald Trump.
Scientists attribute at least part of the rise in autism to increased awareness and an expanding definition of the disorder. Researchers have also been investigating environmental factors.
Studies on acetaminophen have been inconclusive as to any autism link.
Research last month by experts from Icahn School of Medicine at Mount Sinai and Harvard’s TH Chan School of Public Health analysed 46 previously published epidemiological studies.
They found that of these, 27 reported links between use of acetaminophen by pregnant women and an increased risk of neurodevelopmental disorders such as autism.
Another nine showed no significant link, while four others indicated protective effects.
Dr Nathaniel DeNicola, an OB-GYN who advises the American College of Obstetricians and Gynecologists, told the New York Times this study did not change much.
“The conclusion of the paper is that Tylenol should be used judiciously in the lowest dose, least frequent interval”, he said, adding that this was “exactly the current standard of care for Tylenol”.
In 2021, an international group of 91 scientists and clinicians published a consensus statement urging caution on use of the pain reliever during pregnancy.
But a 2024 study in the Journal of the American Medical Association involving 2.4 million children born in Sweden found no evidence to support a causal link.
Tylenol’s maker has faced hundreds of lawsuits claiming the medication can cause autism if mothers take it during pregnancy.
But last August, a US judge dismissed all the cases in federal court after finding that expert witnesses lacked scientific evidence for their claims.
The plaintiffs are challenging that ruling in a US appeals court.