Background

Over the last few decades, autism rates have been steadily rising. In 2000, roughly 1 in 150 children in the United States born in 1992 were diagnosed with autism. In 2020, 1 in 36 children born in 2012 were diagnosed, CDC data shows.

In April, Kennedy announced that HHS had launched a "massive testing and research effort" to determine the cause of rising autism rates, setting an initial deadline of September.

Although autism experts say that this increase could largely be due to better screening and diagnoses, other factors, such as people taking medications during pregnancy that can affect the developing fetus and older fathers being more likely to pass along genetic mutations, could also be contributing to rising autism rates. However, the validity and extent of these factors are still being studied.

"We are going to look at vaccines, but we are going to look at everything. Everything is on the table," Kennedy said. "Our food system, our water, our air, different ways of parenting, all the kind of changes that may have triggered this epidemic."

HHS to link Tylenol use to autism in new report

According to the Wall Street Journal, HHS' report on autism, which is expected to be released later this month, will link the use of Tylenol, a common over-the-counter pain reliever also known as acetaminophen, during pregnancy to autism.

Currently, research on the use of Tylenol during pregnancy and autism is mixed, with some studies suggesting potential risks to fetal development and others finding no association.

For example, in a recent review of 46 previously published epidemiological studies, researchers found that 27 reported links between the use of Tylenol by pregnant people and an increased risk of autism or ADHD in their children. However, a separate study of over 2.4 million children in Sweden did not find an association between Tylenol taken during pregnancy and risk of autism or ADHD.

Currently, the American College of Obstetricians and Gynecologists says that Tylenol is safe to use in pregnancy, but recommends pregnant people consult with their doctors before using it, as with all medications. 

Commentary

In a statement, Kenvue, the parent company of Tylenol's manufacturer, said the health and safety of the people who use its products are of top importance and that leading medical groups have agreed that Tylenol is safe to use during pregnancy.

"We have continuously evaluated the science and continue to believe there is no causal link between acetaminophen use during pregnancy and autism," Kenvue said.

Health experts have also spoken out against designating one specific cause of autism, which has been linked to hundreds of different genes and could be influenced by numerous environmental factors.

"To simplify it and boil it down to, 'It's just acetaminophen' is disingenuous and misleading," said Alycia Halladay, chief science officer at the Autism Science Foundation.

"We know that autism is incredibly complex: It's the result of genetics and environmental factors that affect the way people respond to the world," Halladay added. "I think we need to move away from studies that simplify it down to one exposure without any other considerations."

Currently, health experts say that more research is needed to understand how environmental factors, including medications, diet, and chemicals, can influence the development of autism and other neurodevelopmental conditions in children.

"Tylenol came into the picture because its use very rapidly increased," said Zeyan Liew, an associate professor of epidemiology at the Yale School of Public Health, "but it's just one of many thousands of environmental factors we need to study."