In his second day of confirmation hearings, Robert F. Kennedy Jr., President Donald Trump’s pick to lead the Department of Health and Human Services, refused to say that vaccines do not cause autism — despite a large body of evidence showing there is no link. He also pointed to a flawed paper to suggest that there is credible evidence to claim vaccines cause the disorder.
Unlike his Jan. 29 hearing before the Senate Finance Committee, in which Kennedy was queried about his views about vaccines, but was not forced to speak much about his beliefs about vaccines and autism, significant portions of the Jan. 30 Senate Committee on Health, Education, Labor and Pensions hearing focused on the issue.
As we’ve detailed, Kennedy has regularly repeated long-debunked claims about vaccines and autism, including as the founder and former chairman of Children’s Health Defense, a nonprofit that spreads vaccine misinformation.
Recently, however, he has tempered his statements on vaccines, insisting he is not anti-vaccine — and, as he said in the hearings — is “pro-safety.”
In the HELP committee hearing, Kennedy declined to disavow a link between vaccines and autism, despite pressure from lawmakers, including from the committee chairman, Sen. Bill Cassidy, a physician from Louisiana.
“Will you reassure mothers unequivocally and without qualification, that the measles and hepatitis B vaccines do not cause autism?” Cassidy asked.
“If the data is there, I will absolutely do that,” Kennedy said, after being pressed to give a yes or no answer.
Cassidy assured him it was. “If you show me data,” Kennedy continued, “I will be the first person to assure the American people … that they need to take those vaccines.” He also vowed in that case to “apologize for any statements that misled people otherwise.”
Sen. Bernie Sanders, an independent from Vermont and ranking member of the committee, continued Cassidy’s line of inquiry, noting “dozens of studies done all over the world that make it very clear that vaccines do not cause autism,” and asking if Kennedy agreed with that.
“As I said, I’m not going to go into HHS with any preordained,” Kennedy said, before Sanders interrupted to ask again. Kennedy again said that he would need to be shown the data.
Other senators appeared to support Kennedy in arguing that he was correct to question whether vaccines might cause autism.
“There’s an issue that I have as a father of six, that when my kids come out from getting their vaccines, they look like a freaking pin cushion,” Sen. Markwayne Mullin, a Republican from Oklahoma, said. “I think there’s a reason we should be questioning this.”
Kentucky Republican Sen. Rand Paul, who is an ophthalmologist, argued that because “we don’t know what causes” autism, investigation of vaccines should continue.
But as we’ve explained, and as several senators pointed out, data demonstrating that there is no link between vaccines and autism already exists. Different vaccines and vaccine ingredients have been repeatedly tested, showing no connection.
One particularly large 2019 study of the MMR, or measles, mumps and rubella, vaccine, for example, covered all children born in Denmark to Danish-born mothers between 1999 and 2010 with at least several years of follow-up. It found no increased risk of autism among vaccinated children, including in kids with siblings with autism and other risk factors.
The original 1998 study that sparked the vaccine-autism concern was found to be fraudulent, and it was retracted. On top of that, there is a lack of biological plausibility, as research now shows that autism begins to develop before childhood vaccines are given.
Flawed Paper
Near the end of the more than three-hour hearing, Cassidy confronted Kennedy with a 2014 meta analysis, reminding him of his promise that he would say vaccines do not cause autism if shown the data.
“The title tells it all,” Cassidy said of the study, which was published in the journal Vaccine by researchers in Australia. “Vaccines are not associated with autism: An evidence-based meta-analysis of case-control and cohort studies.”
“You show me those scientific studies, and you and I can meet about it,” Kennedy said. “There are other studies as well, and I’d love to show those to you. There’s a study that came out last week of 47,000 9-year-olds in the Medicaid system in Florida — I think a Louisiana scientist called Mawson — that shows the opposite. There are other studies out there. I just want to follow the science.”
Contrary to Kennedy’s claim that “there are other studies out there,” the literature on vaccines and autism is not mixed, unlike many other scientific topics. As David Mandell, a psychiatric epidemiologist at the University of Pennsylvania, previously told us, “Every single rigorous study we have” shows “no association” between autism and vaccination.
The specific paper Kennedy cited — which claims to have found that “[v]accinated children were significantly more likely than the unvaccinated to have been diagnosed” with autism and a variety of other neurodevelopmental disorders — is not rigorous.
“I have read this paper carefully, and it has so many severe methodological issues, it clearly should not have passed any legitimate peer review,” Jeffrey S. Morris, director of the division of biostatistics at the University of Pennsylvania’s Perelman School of Medicine, told us.
The paper was published on Jan. 23 in Science, Public Health Policy and the Law, an outlet that claims to be a peer-reviewed journal, but as we have noted before, is not available on PubMed Central, the National Institutes of Health’s database of biomedical research, nor indexed on MEDLINE, which requires some evaluation of journal quality. The editor-in-chief and other board members, including the section editor for the paper, are well-known spreaders of vaccine misinformation.
The two authors, including lead author Anthony Mawson, are affiliated with Chalfont Research Institute in Mississippi, which does not have a website and appears to use a residential home as a mailing address, based on IRS records. Both authors have previously published work on vaccines that has been retracted. The paper was funded by the National Vaccine Information Center, an anti-vaccine group.
Using Florida Medicaid claims data, the paper compared how common certain neurodevelopmental disorders, or NDDs, including autism, were in 9-year-old children born between 1999 and 2002 who were considered vaccinated with those who were not.
Children were counted as vaccinated if they ever had a health care visit with a billing code for a vaccine in their Medicaid claim records. The authors did not have information on which vaccines were administered or whether children might have been vaccinated outside of the Medicaid system.
The authors reported finding that about 28% of vaccinated kids had been diagnosed with at least one NDD, compared with 11% for unvaccinated children. For autism specifically, the authors said vaccinated kids were about 2.7 times more likely to have a diagnosis than those who never had a vaccine billing code in their Medicaid records.
Morris, however, said several features made the paper’s primary analysis “severely flawed from a biostatistical standpoint.”
One of the biggest issues, he said in an email, is that the analysis “ignores all confounding factors that might influence both propensity to [be] vaccinated and propensity to be identified with a NDD, and treats the 90% of the population who were vaccinated by age 9 as equivalent in every way except vaccination to the 10% who remained unvaccinated at age 9 (according to Medicaid records).”
Of these confounding factors, Morris said, “by far the most important one” is a person’s health care utilization status, which he said should have been available in the data. People who use more health care are more likely to get vaccinated and to have a condition diagnosed and treated.
Other factors, he said, include: race, since there are known disparities in autism diagnoses; and genetics and family, because parents are likely to vaccinate their children similarly and autism can run in families.
In addition, Morris said the authors didn’t “even check whether the NDD diagnosis occurred before or after the first vaccination record.”
“The authors’ ignoring of all current literature going against their hypothesis is another severe flaw,” he said, “as is their citation of their own previous paper that was retracted.”
Other scientists have also noted many of these problems and others with the Mawson paper.
In contrast, Morris pointed to the 2019 Danish study, which he said “was much more rigorously done.” That study, he explained, used actual medical records; pulled from a much wider population, rather than the Medicaid population of one state; adjusted for many confounders, including an autism risk score; and used time-varying vaccination status to properly classify a person as unvaccinated until after their first vaccine.
Cassidy, who briefly took a look at the Mawson study after Kennedy mentioned it, said during the hearing that it “seems to … have some issues.” He then said that he was “struggling” with Kennedy’s nomination.
“Does a 70-year-old man, 71-year-old man who spent decades criticizing vaccines and who is financially vested in finding fault with vaccines,” Cassidy said, “can he change his attitudes and approach now that he’ll have the most important position influencing vaccine policy in the United States?”
Despite the Mawson paper’s dubious origin and many flaws, its purported results have been widely shared on social media. “Pro-Vaxxers Need to WAKE UP,” declared one Instagram post.
Children’s Health Defense, the nonprofit Kennedy led until last month, also plugged the paper in a story on its website, calling it “jaw-dropping” in the headline and quoting one of its own scientists as saying that it “is unignorable simply by the soundness of its methods.”
CHD also quoted an epidemiologist we have previously fact-checked — and who had a paper retracted and then republished in the same outlet as the Mawson paper — as saying that the study’s results “warrant further study by the new U.S. administration.”
“I’m coming in here to get rid of the conflicts of interest within the agency, make sure that we have gold-standard evidence-based science,” Kennedy said in the hearing, asking senators to “show me where I’m wrong … show me a single statement I’ve made about science that is erroneous.” He was wrong to deny the science about vaccines and autism, and the study he cited is anything but the gold standard.
Editor’s note: FactCheck.org does not accept advertising. We rely on grants and individual donations from people like you. Please consider a donation. Credit card donations may be made through our “Donate” page. If you prefer to give by check, send to: FactCheck.org, Annenberg Public Policy Center, 202 S. 36th St., Philadelphia, PA 19104.