In a contentious interview on CNN’s “State of the Union,” Health and Human Services Secretary Robert F. Kennedy Jr. made several false, misleading and baseless claims about the origins of Lyme disease and the respiratory syncytial virus, the COVID-19 pandemic, and what the science shows about autism, vaccination and acetaminophen use during pregnancy.
On the Aug. 2 show, Kennedy had several disagreements with host Dana Bash, with Bash challenging the health secretary’s assertions and Kennedy saying that Bash was wrong. We’ll sort out the facts.
- Kennedy baselessly claimed that Lyme disease and respiratory syncytial virus infections came from lab research. There’s no evidence for this, and the diseases have long affected humans.
- The U.S. doesn’t have “the highest death rate from COVID of any nation on Earth,” as he said. It has the highest rate among large, wealthy nations, but is 14th among all nations, per one analysis.
- Kennedy asserted that effective treatments were suppressed during the COVID-19 pandemic, likely referring to ivermectin and hydroxychloroquine, as he has before. Multiple clinical trials have shown that neither drug improved outcomes in COVID-19 patients.
- He falsely suggested that COVID-19 vaccines don’t protect children from the virus, asking Bash to cite “one study that shows that children were protected.” Multiple studies have shown that vaccination reduces the odds of infection and severe disease among children and adolescents.
- Kennedy said he has “never questioned the efficacy of the MMR,” or measles, vaccine. But on a few occasions, he has suggested the vaccine wasn’t that effective or that it wasn’t necessary.
- He brought up an unproven link between Tylenol use during pregnancy and autism. While some studies have found an association, they don’t establish causation, and a growing number of studies point away from acetaminophen as a cause of autism.
- Kennedy misleadingly said that scientists have not tested vaccines other than the MMR vaccine for autism. Scientists have tested many vaccines while investigating specific hypotheses for how the shots might cause autism. None of the studies has shown any credible link.
We sent HHS several questions about Kennedy’s claims, but we haven’t received a response.
Baseless Claims About RSV and Lyme Disease
Kennedy baselessly claimed that two infectious diseases — Lyme disease and respiratory syncytial virus infections — arose from gain-of-function research. Such research generally refers to potentially risky experiments in which a virus or other pathogen becomes more dangerous or transmissible in people. But the microbes that cause these diseases have long sickened humans. There’s no evidence they came from a lab, let alone from gain-of-function research.
Kennedy also asserted that gain-of-function research caused the coronavirus pandemic. As we’ve written previously, there’s no definitive proof of how the virus that causes COVID-19 arose, but substantial evidence points toward a natural origin and not a lab leak. Scientists have previously told us that it’s virtually impossible that the coronavirus was engineered; almost all U.S. intelligence agencies have also assessed that the virus was not genetically engineered.
“Clearly, COVID-19 pandemic — and many other global pandemics that we have — have come from gain-of-function research,” the HHS secretary said. “The RSV epidemic that we have that is the biggest killer of kids in this country today came from these kind of experiments. The Lyme disease almost certainly came from this kind of research.”
“RFK Jr’s assertions that RSV and Lyme disease (caused by the bacterium Borrelia burgdorferi) arose from gain of function research are unquestionably false,” Dr. Ferric Fang, a physician-scientist and microbiologist at the University of Washington School of Medicine, told us in an email.
Kennedy has been making unfounded claims about lab origins for RSV, Lyme disease and other infectious illnesses since before he became HHS secretary.
Fang said that the tick-borne bacterium that causes Lyme disease has “ancient” origins, “even though human Lyme disease was not recognized until the 1970s.” A 2012 study shows evidence of the Lyme-causing bacterium in 5,300-year-old remains of the Tyrolean Iceman found in the Alps, he said. He also pointed to genomic research on bacteria from ticks collected between 1984 to 2013 indicating the Lyme-causing microbes have been in North America for around 60,000 years.
The history of the Lyme-causing bacterium “makes it quite clear that it did not arise from a lab,” Fang said.
RSV’s history also does not indicate a lab origin.
Fang said that RSV is related to a cattle virus and that the evolutionary paths of the human and bovine versions of the virus diverged approximately 450 years ago. Genetic evidence also shows that human RSV split into two major subgroups around 250 years ago, he explained, before further branching off into more subtypes.
“Understanding the evolutionary history of a virus and seeing the intermediate steps allows you to realize that it arose naturally and was not a human construct,” Fang said. Archived samples of human tissues show evidence of RSV infection “dating back to 1931,” he added.
In 2021, Children’s Health Defense, the nonprofit Kennedy founded and formerly chaired that misleads about vaccination, published an article claiming that RSV came from chimpanzees in a lab being used for vaccine research and development, although it did not describe any gain-of-function research. The article misconstrues the history of RSV’s discovery.
“An outbreak in chimpanzees at the Walter Reed Army Institute of Medical Research in 1955 led to RSV’s discovery,” Fang explained. Researchers soon thereafter identified the same virus in children with pneumonia. However, the researchers “ultimately concluded that the captive chimpanzees had been infected with the same virus acquired from humans,” Fang said.
“Given that the chimpanzee colony was in a research environment where the animals are maintained in a controlled environment,” the authors of a 2025 commentary, including one of the scientists who discovered RSV, wrote, it was plausible the chimpanzees were sickened accidentally by infected humans who cared for them.
Also contrary to Kennedy’s claim, RSV is not “the biggest killer of kids in this country today.”
“RSV is not a major cause of childhood mortality in the US,” Fang said. “The leading causes of death in US children are accidents, congenital disorders, cancer and suicide,” he added, citing statistics from the Centers for Disease Control and Prevention.
RSV historically has been estimated to kill 100 to 300 children under 5 years of age annually. The virus was the top cause of hospitalization in infants, although data indicate the introduction of immunizations beginning in 2023 reduced hospitalizations.
COVID-19 Death Rate Not Highest in U.S.
Kennedy wrongly said that the U.S. has “the highest death rate from COVID of any nation on Earth.” Bash pushed back on the claim, saying that “there are other countries that had higher” death rates. Bash is correct.
According to data collected by Johns Hopkins University & Medicine through March 2023, there were 13 countries with higher death rates than the U.S. when measured as deaths per 100,000 population. Some of those countries include Peru (with the highest rate), Bulgaria, Hungary, Bosnia and Herzegovina, Slovakia and Lithuania. When using the case-fatality ratio, which is deaths per 100 confirmed COVID-19 cases, more than 90 countries have a higher mortality rate than the U.S.
Kennedy would have been correct to say that the U.S. had the highest death rate among large, wealthy nations, as a 2022 New York Times analysis found. The Times also found that the U.S. had a smaller share of people fully vaccinated compared with the other wealthy countries. The U.S. also had the highest number of reported deaths, at 1.1 million people.
Repeat Claims About Unproven Drugs for COVID-19
Kennedy falsely asserted that effective COVID-19 therapeutics were suppressed during the pandemic. Though he didn’t specify, he was likely referring to the antiparasitic drug ivermectin and the antimalarial drug hydroxychloroquine. As we’ve written before, Kennedy has previously made similar claims about both drugs — even though clinical trials have found no evidence that either one is effective against COVID-19.
“If we had listened to those doctors during the COVID pandemic, we would have saved potentially millions of lives,” he said during the CNN interview. “There were therapeutics out there that were working. There were doctors that were having no deaths from COVID and treating, in some cases, thousands of patients. And we weren’t listening to them. Instead, we were doing the opposite. We were shutting them down.”
As we’ve previously explained, multiple large, randomized controlled trials — considered the gold standard of evidence in medicine — have found that neither ivermectin nor hydroxychloroquine reduced deaths or otherwise improved outcomes among COVID-19 patients. The federal government funded some of those studies. The Food and Drug Administration briefly authorized hydroxychloroquine for emergency use in 2020, but revoked that authorization after a clinical trial and other evidence showed it was unlikely to be effective in treating COVID-19.
The FDA did approve other drugs for treating COVID-19, including the antiviral drugs Veklury (remdesivir) and Paxlovid, after they were found to be effective in clinical trials.
False Suggestion COVID-19 Vaccines Don’t Benefit Kids
At one point, Kennedy interrupted Bash several times to suggest, falsely, that there’s no evidence COVID-19 vaccines protect children from the virus.
“You think the COVID vaccine protected children?” Kennedy asked the CNN anchor, adding a moment later: “Can you show me one study that shows that children were protected by the COVID vaccine? That that vaccine did more good than harm to children? Can you show me one study that shows that?”
We’ve written before about Kennedy’s misleading statements about the COVID-19 vaccine and children, in which he has exaggerated the risks of the shot while downplaying the risks that the virus itself poses to children.
While children generally face lower risks from COVID-19 than adults, they can still become seriously ill, and more than 1,800 U.S. children have died from the disease. Multiple clinical trials and other studies have found that COVID-19 vaccines reduce the risk of infection and severe disease among children and adolescents. For example, a 2024 study estimated that when the Omicron variant was circulating, children ages 5 to 11 who received the Pfizer-BioNTech vaccine were 74% less likely to have a documented infection, 76% less likely to develop moderate or severe disease and 85% less likely to be admitted to an ICU with COVID-19.
The CDC’s own website, on a page last updated in June 2025, states that “COVID-19 vaccines help keep children from getting really sick from COVID-19” and that “many children should get an updated COVID-19 vaccine.”
As we’ve written before, serious side effects linked to the vaccines can happen, but are extremely rare.
Past Statements on MMR Effectiveness
In responding to Bash’s questions about the large measles outbreaks in the U.S. in the past two years and whether Kennedy accepted some responsibility for that, Kennedy said, “I’ve never questioned the efficacy of the MMR vaccine.” That’s not entirely accurate.
As we found in compiling a timeline of Kennedy’s comments on measles and the measles, mumps and rubella vaccine, it’s true that he has often cited the high effectiveness of the vaccine in preventing measles. His criticisms and inaccurate claims about the vaccine are mainly related to its safety. But there are a few instances when he suggested the vaccine wasn’t that effective or that it wasn’t necessary.
In 2021, Kennedy wrote in a foreword to a book by Children’s Health Defense, the group he founded, that “American and global consumers of measles vaccines” have been “misled by the pharmaceutical industry and their captured government agency allies into believing that measles is a deadly disease and that measles vaccines are necessary, safe, and effective.”
“The Measles Book explodes this propaganda,” he continued, saying that the book would “reveal a disease that is rarely life threatening and a vaccine that is largely unnecessary but which carries real risks for the children mandated to take them.” He said the benefits of the vaccine had been “exaggerated,” a statement he had also made in September 2019 in a post on the CHD website. More recently, in a March 2025 Fox News interview, Kennedy wrongly said that the MMR vaccine’s effectiveness “wanes about 4.5% per year,” claiming that this was a reason for measles outbreaks, along with people not being vaccinated.
In the CNN interview, when pressed by Bash to look into the camera and tell parents to vaccinate their kids for measles, “because it is safe and it will help them save their children’s lives,” as Bash put it, Kennedy said: “A measles vaccine is effective. It stops measles in about 97% of the cases. People should get vaccinated.”
Kennedy didn’t say the vaccine was safe, but the CDC states on a webpage last updated in April: “The MMR vaccine is very safe.” Yet, another CDC webpage about autism, modified by Kennedy last year, casts doubt on the robust evidence that the MMR vaccine isn’t linked to autism.
An Unproven Link Between Tylenol and Autism
Kennedy also referred to an unproven link between Tylenol and autism. Other administration officials, including Trump himself, have made similar claims.
“There’s 73 studies out there that link Tylenol exposure during later pregnancy and during the perinatal period to autism onset,” Kennedy said during his interview with Bash.
As we’ve written before, some studies have found an association between acetaminophen use during pregnancy and certain neurodevelopmental conditions, including autism. But those studies don’t establish causation, and a growing number of other studies point away from acetaminophen as an autism cause. A recent study of more than 100,000 children in Hong Kong, for instance, found no association between acetaminophen use during pregnancy and autism once siblings were used to control for differences between families.
Major medical associations, including the Society for Maternal-Fetal Medicine and the American College of Obstetricians and Gynecologists, continue to endorse acetaminophen as the “first-line medication for the treatment of pain and fever during pregnancy.” Failing to treat pain and fever during pregnancy comes with risks for mothers and babies.
“As with all medications taken during pregnancy,” the groups advise, “patients should use the lowest effective dose of acetaminophen for the shortest duration necessary.”
No Link Between Autism and Vaccines After Extensive Study
In a heated exchange with Bash, Kennedy misleadingly insisted that many vaccines have not been studied for whether they might cause autism. While each vaccine has not been examined individually, every major hypothesis for how vaccines might cause autism has been tested in numerous studies, with no credible links to autism.
“You have been fooled. Your statement that this has been studied is not true,” he told her. “It’s categorically not true.”
He pointed to a 2012 review from the Institute of Medicine – now the National Academy of Medicine – that he said found that “none of the eight vaccines that are administered during the first six months of life have ever been studied for [a] relationship to autism.”
“Show me one of the studies that’s been done on the first eight — the vaccines during the first six months of life,” he said to Bash. “You will not find them. The National Academy of Sciences states they do not exist.”
He later claimed that the measles, mumps and rubella, or MMR, vaccine is the “only” vaccine “that has been studied.”
This is misleading. What Kennedy is likely referring to is that many vaccines have not been individually tested for whether they might cause autism. This does not mean, however, that they haven’t been tested at all. Instead, many have been tested for autism in studies investigating particular vaccine ingredients, since that is how they were suspected of potentially causing autism.
Kennedy made a similar argument when he amended a CDC webpage in November to misleadingly say that “’vaccines do not cause autism’ is not an evidence-based claim because studies have not ruled out the possibility that infant vaccines cause autism.” (The CDC recently modified the page in an effort to assuage Republican Sen. Bill Cassidy, although the main message of the page remains.)
As we’ve noted before, scientists work off of particular hypotheses for how vaccines might cause autism. The MMR vaccine has been thoroughly investigated as an individual vaccine because the notion that vaccines might cause autism began with that vaccine via what would turn out to be a fraudulent study from the British researcher Andrew Wakefield.
Following the initial focus on the MMR vaccine, suspicion shifted to vaccine ingredients such as thimerosal, a mercury-based preservative that was in several childhood vaccines in very small doses, mostly before 2001, as well as aluminum, which is present in small amounts in certain non-live vaccines to boost the immune response.
Many studies investigating these hypotheses have studied several infant vaccines, including those that protect against hepatitis B, Haemophilus influenzae type b (Hib), pneumococcus (PCV), and diphtheria, tetanus, and pertussis (DTaP). Neither ingredient has shown a link to autism.
Yet other studies have looked at the larger vaccination schedule as a whole, looking for any sign that more vaccines are problematic. They, too, have not found any link to autism.
Because of the totality of the evidence, many scientists are comfortable saying that vaccines don’t cause autism, even though not every vaccine has been tested individually and despite the fact that it’s technically impossible to say whether a vaccine doesn’t do something.
Indeed, as Bash noted during the interview, the National Academies has agreed with the CDC’s prior statement, writing in response to the CDC’s website change in November that “based on our body of work on this topic and the overwhelming scientific consensus, we support the statement that vaccines do not cause autism.”
Incorrect Claims About National Academy Report
It’s worth noting that Kennedy’s specific claims about the National Academy of Medicine/Institute of Medicine report are also incorrect.
He said the report “found two studies, one on the DTP vaccine that show[s] that it does cause autism, and one on the hepatitis B vaccine that again suggests that it does cause autism,” adding that IOM “dismissed those two studies because they were based on CDC’s database.”
The group’s most recent report on vaccine side effects, published in 2012, was only charged with looking into autism as a potential side effect for two vaccines. It did not comment on autism and any other vaccines because the committee was not asked to do so.
The 2010 hepatitis B vaccine study Kennedy is likely thinking of, which the CDC webpage revised under Kennedy highlights, was retracted this May, after an “independent statistical reviewer concluded that due to fundamental methodological flaws the study’s conclusions are unsound.” It had based its conclusions on a selected sample of just 31 autism cases, among other issues.
Previously, the study was mentioned in a 2014 review prepared for the Agency for Healthcare Research and Quality, a subagency of HHS. In another similar review, published in Pediatrics, the same set of authors said the study was at “high risk of bias and low quality,” when explaining why they did not think this was evidence that the vaccine caused autism.
As for DTaP, the 2012 IOM report said it reviewed one study that it did not consider in its evaluation because “it provided data from a passive surveillance system and lacked an unvaccinated comparison population.” That study, from 2004, does not show that diphtheria, tetanus and pertussis vaccines cause autism.
Rather, it compared reports to the Vaccine Adverse Event Reporting System for the older whole cell vaccine versus the newer acellular vaccine for a litany of potential side effects, finding the older vaccine had about four times more reports of autism than the newer vaccine during a three-year period. As we’ve explained before, the voluntary reports to VAERS can be submitted by anyone, regardless of whether it’s likely the vaccine caused the event. The newer vaccine has been the only vaccine given for that set of diseases since 2001.
The study was authored by Dr. Mark Geier and his son, David, who have written numerous papers claiming vaccines cause autism that have been retracted or criticized for serious methodological flaws. The duo operated a clinic that gave a testosterone-suppressing drug and other unproven treatments to autistic children, at least partially based on the incorrect notion that thimerosal in vaccines causes autism. Kennedy has hired David, who does not have an advanced science degree and was fined for practicing medicine without a license, to analyze vaccine safety data for HHS.
In 2004, when the IOM concluded that the evidence “favors rejection of a causal relationship between thimerosal-containing vaccines and autism,” the reviewers noted that several other studies from the Geiers, which purported to show a link to autism via thimerosal-containing DTP or DTaP vaccines using VAERS, had “serious methodological limitations that make their results uninterpretable.”
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, P.O. Box 58100, Philadelphia, PA 19102.
