CDC Will Study Possible Link Between Vaccines and Autism, Pledges to ‘Leave No Stone Unturned’

The CDC confirmed it plans to study the possible link between vaccines and autism after Reuters reported on the plan late Friday.

Mar 11, 2025

The Centers for Disease Control and Prevention (CDC) confirmed it plans to study the possible link between vaccines and autism, after Reuters reported on the plan late Friday, citing two sources inside the agency.

In response to the Reuters story, the CDC and the U.S. Department of Health and Human Services (HHS) provided an identical statement:

“As President Trump said in his Joint Address to Congress, the rate of autism in American children has skyrocketed. CDC will leave no stone unturned in its mission to figure out what exactly is happening. The American people expect high quality research and transparency and that is what CDC is delivering.”

The revelation came days after President Donald Trump, in an address to Congress, referred to the rising rate of autism in the U.S. Trump, citing CDC data showing that 1 in 36 U.S. children have autism, said HHS Secretary Robert F. Kennedy Jr., is well suited to lead efforts to study the increase.

“There’s something wrong,” Trump said. “So, we’re going to find out what it is, and there’s nobody better than Bobby [Kennedy] and all of the people that are working with you.”

According to The Washington Post, Trump administration officials asked the CDC to perform the study. Newsweek reported that it is “unclear” whether Kennedy is involved in the new study. However, HHS oversees federal health agencies, including the CDC.

Karl Jablonowski, Ph.D., Children’s Health Defense (CHD) senior research scientist, applauded “the CDC’s newfound curiosity in vaccines and autism.” He said the U.S. “passed an inflection point” in the 1990s, where autism “went from being a rare disease to a more common one” that has been “increasing exponentially ever since.”

“When is an appropriate time to conduct a large study on vaccines and autism? Apparently, two generations later,” Jablonowski said.

Sayer Ji, chairman and co-founder of the Global Wellness Forum, called the news a “pivotal moment, not just in the scientific exploration of vaccine safety, but in the broader issue of public trust in our institutions.”

Ji said the CDC’s plan for a large-scale study “is an implicit admission that prior investigations may have been insufficient, biased or incomplete.” He said the new study “could represent a breakthrough moment” in “resolving this critical health question” and “restoring faith in the integrity of scientific inquiry itself.”

‘A seismic shift toward accountability’

According to the Post, the CDC will conduct the study using data from the Vaccine Safety Datalink, a database of patient health records. The Vaccine Safety Datalink draws on data from 13 U.S. healthcare organizations, CNN reported.

Biologist Christina Parks, Ph.D., said the study should examine the CDC’s childhood vaccination schedule.

“The cumulative effect of giving multiple vaccines at once as well as over a short period of months has not been studied as a potential contributing factor to autism,” Parks said. “Vaccines have the potential to alter a child’s immune system in ways that are unexpected.”

Parks referred to studies performed in 1970 and 1987 that found autism rates of 0.7 and 3.3 children per 10,000, respectively. “If autism were as prevalent then as it is now, we should have a large number of older autistic adults, which we do not,” Parks said.

Brian Hooker, Ph.D., chief scientific officer for CHD, suggested the CDC study should use an unvaccinated control group. Hooker cited his experience performing research using data from the Vaccine Safety Datalink, noting that the database already contains data on unvaccinated children.

A 2021 study co-authored by Hooker found that vaccinated children were significantly more likely than unvaccinated children to be diagnosed with autism.

Ji said any CDC study examining a possible vaccine-autism link should reflect Kennedy’s recent calls for “gold-standard science.”

He said:

“It must be a true gold-standard study. The methodology must be rigorous, transparent and independent, with no industry or government interference. It should be a prospective, controlled, long-term study comparing fully unvaccinated and vaccinated populations.”

Hooker said the CDC has previously not made data from the Vaccine Safety Datalink available to the public, even though it is taxpayer-funded.

“We’ve never had access to the Vaccine Safety Datalink. We’ve never had access to such a gold-standard database, and that thing takes $50 million worth of tax dollars to maintain every year. It should be open to the public,” Hooker said.

Ji said many past vaccine safety studies were flawed due to a lack of transparency.

“Historically, vaccine safety studies have been marred by selective reporting, data manipulation and redacted findings. Kennedy has long advocated for open access to government data, and if this study follows through on that promise, it would be a seismic shift toward accountability,” Ji said.

Rise in autism cannot simply be attributed to ‘better diagnosis’

Reuters attributed the rise in autism rates to “more widespread screening and the inclusion of a broader range of behaviors to describe the condition.”

Research scientist and author James Lyons-Weiler, Ph.D., said such claims are “pure disinformation.”

“No rigorous study has shown that these factors are responsible,” Lyons-Weiler said.

“These criteria cannot explain the 7% increase in autism following the removal of vaccine exemptions from California, which has 1 in 22, the highest rate among all states,” Lyons-Weiler said.

Ji said that prior studies claiming to debunk the vaccine-autism link should be called into question, noting that many such studies “suffer from conflicts of interest, flawed methodologies and a lack of truly unvaccinated control groups.”

According to Hooker, many previous studies were flawed because they focused only on a limited number of vaccines and vaccine components.

“The CDC and most of the open peer-reviewed literature focuses on one vaccine and one vaccine component, the MMR [measles-mumps-rubella] vaccine and thimerosal” — a mercury-based preservative used in some vaccines. A 2013 study found a link between thimerosal exposure and the risk of an autism diagnosis.

Recent independently performed studies have indicated a connection between vaccines and autism.

A peer-reviewed study published in Science, Public Health Policy and the Law in January found that vaccinated children have a 170% higher chance of being diagnosed with autism compared to unvaccinated children. The study also found that the autism risk increases in children with a higher number of vaccinations.

A ‘new era of openness’

Reuters quoted Dr. Wilbur Chen, a professor at the University of Maryland School of Medicine and former member of the CDC’s vaccine advisory panel, who suggested the CDC’s new study could fuel vaccine hesitancy.

“It sends the signal that there is something there that is worth investigating, so that means there must be something going on between vaccines and autism,” Chen said.

But other experts suggest that such statements conceal concerns that vaccines may not be as safe as frequently claimed.

“Americans and those who receive our vaccines overseas should be able to have confidence that American products, especially biologics that are injected into children, meet the highest safety standards,” Parks said. “By addressing parent concerns, the CDC can help to reestablish trust in its guidelines.”

“If the vaccines are safe, transparency should increase confidence, not the opposite,” Ji said. “If vaccines are as safe as claimed, then the data should confirm that and bolster confidence. The fear of ‘hesitancy’ suggests a deeper concern that the results may contradict the official narrative.”

Hooker said the new CDC study is representative of a “new era of openness” and will “encourage greater faith in our institutions and their recommendations regardless of where they fall.”

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