Trump links autism to Tylenol and vaccines, claims not backed by science

At an unusual White House press conference, Trump urged pregnant women not to take Tylenol and warned parents about vaccinating their children too early or with multiple shots at once. “Don’t take Tylenol. Don’t take it,” he told reporters, while describing vaccines as “the largest pile of stuff you’ve ever seen in your life.”

The president admitted he is not a medical professional. His remarks contradicted decades of research and the consensus of medical associations that acetaminophen, the drug’s active ingredient, is safe for use in pregnancy.

Standing alongside Health Secretary Robert F. Kennedy Jr., a vocal critic of vaccines, Trump said the administration would push for a review of vaccine safety and announced government support for leucovorin, a folic acid derivative, as a treatment for autism symptoms.

Medical community rejects claims

Leading health organisations swiftly condemned the president’s remarks. The American Academy of Paediatrics, the American College of Obstetricians and Gynaecologists and autism advocacy groups stressed that existing data do not show Tylenol causes autism, nor that leucovorin is a cure. “These claims only create fear and false hope,” the Coalition of Autism Scientists said.

Drugmaker Kenvue, which produces Tylenol, also rejected the comments, warning of the risks posed to pregnant women if misinformation discourages them from safe treatments. The company’s shares initially fell more than 7% but later recovered some ground in after-hours trading.

Policy and regulatory moves

The Food and Drug Administration (FDA) said it would request updated labelling for Tylenol and generic acetaminophen, cautioning that prenatal exposure may be “associated” with neurological conditions, while emphasising that no causal relationship has been proven. It also issued a letter to doctors, advising cautious use.

Officials said they would explore expanded Medicaid coverage for leucovorin in autism care, even though evidence of its effectiveness remains limited. Early research has shown small benefits in certain metabolic conditions, but experts stress that larger clinical trials are required.

Echoes of past controversies

Trump’s comments drew comparisons to his pandemic-era briefings, when he promoted unproven remedies including disinfectant injections. Independent research has repeatedly shown that vaccines are safe and have saved millions of lives globally by eliminating diseases such as polio and measles.

A Reuters/Ipsos poll this month found that only one in four Americans believes the Trump administration’s latest vaccine recommendations are based on science.

“I have never seen anything quite like this in the vaccine field,” said Dr Norman Baylor, former director of the FDA’s Office of Vaccines Research and Review. Autism specialists also criticised the administration’s stance. “Without credible new evidence, these statements are reckless and potentially harmful,” said Dr Diana Schendel of Drexel University.

What does research say about acetaminophen use during pregnancy?

To date, no conclusive scientific evidence shows that acetaminophen causes autism. Research findings have been mixed: some studies hint at potential risks, while others find no connection at all.

One of the largest investigations, a Swedish study in 2024 covering nearly 2.5 million children, reported no causal relationship between prenatal exposure to acetaminophen and neurodevelopmental disorders such as autism or ADHD.

By contrast, a 2025 meta-analysis reviewing 46 earlier studies suggested a possible association between maternal use of acetaminophen and higher risks of these conditions. However, researchers from the Icahn School of Medicine at Mount Sinai, Harvard University and other institutions stressed that correlation did not mean causation. They recommended that expectant mothers continue using the medicine when necessary, but at the lowest dose and for the shortest duration possible.

More recent large-scale studies in Europe and Japan have indicated that weak associations observed in some reports may actually be due to outside factors — including genetics, parental health, other drugs taken during pregnancy and broader environmental conditions.

What do medical guidelines recommend?

Professional bodies on both sides of the Atlantic, including the American College of Obstetricians and Gynaecologists and the UK’s Royal College of Obstetricians and Gynaecologists, advise that acetaminophen (paracetamol) remains the first-line treatment for pain and fever during pregnancy. They caution against the use of ibuprofen, naproxen and other NSAIDs in the final trimester, noting these can cause birth defects. ACOG urges pregnant women to seek medical guidance before taking any medication.

As one autism researcher put it: “We have strong evidence that acetaminophen is not the cause of autism.”

What are the risks of not treating fever in pregnancy?

Failing to control fever or significant pain during pregnancy can itself pose serious dangers. Studies show untreated maternal fever is associated with birth defects, including heart malformations, abdominal wall defects and neural tube problems affecting the brain and spine. Untreated fever and pain have also been linked to preterm delivery, low birth weight and miscarriage. For mothers, ignoring these symptoms may lead to high blood pressure, dehydration, anxiety, depression and other complications.

Why is the issue back in focus?

The debate has been reignited by lawsuits in the United States. Parents and advocacy groups filed cases alleging that Tylenol and generic acetaminophen, manufactured by Kenvue, could cause autism or ADHD and that retailers failed to warn consumers.

In December 2023, a U.S. federal judge ruled that expert testimony supporting these claims lacked scientific credibility. By August 2024, all federal cases were dismissed. However, the matter is not yet fully settled: a US appeals court is scheduled to review the decision in the coming months.