You’ve almost certainly had RSV. Most of us catch it before we turn 2. Usually it feels like a cold: runny nose, cough, maybe a fever. But RSV (short for “respiratory syncytial virus”) can take a dangerous turn. In the United States, it puts more babies in the hospital than any other virus and kills thousands of seniors each year. Cases tend to climb as the weather cools—so, right about now.
Health Secretary Robert F. Kennedy Jr. seems to be intent on spreading the word about RSV: He brought up the virus during interviews on both CNN and Fox News in August. He could have used those appearances to remind viewers about the RSV vaccine, which the FDA first approved in 2023 and the CDC recommends for older adults and for women in the later stages of pregnancy during the fall and winter. Instead, Kennedy made two false statements. First, on CNN, he called RSV “the biggest killer of kids in this country today.” (According to the CDC, it isn’t; cancer claims more children’s lives.) His other whopper was weirder: In both appearances, he blamed RSV on a scientific experiment gone wrong, saying on Fox that it “came from a laboratory” and on CNN that it came from gain-of-function experiments, or something like them.
To be clear, RSV did not leak from a lab. But Kennedy has been repeating this fiction on podcasts for years, and he included it in his 2021 book, The Real Anthony Fauci. Even in that compendium of dubious and debunked assertions, Kennedy’s theory about RSV—which involves nonhuman primates, a military research facility, and, of course, vaccines—stands out. It’s a case study in how, as an anti-vaccine activist, he has trafficked in half truths and half-baked narratives, and how he relies on loyalists who reinforce his beliefs rather than experts who can challenge them. Kennedy could easily have consulted the historical record or reached out to subject-matter experts. Instead, as he’s done frequently during his nearly two years as health secretary, he parroted the flawed research of an activist ally.
Kennedy claims RSV originated in captive chimpanzees, and then spread to humans. On a 2023 podcast, he said scientists deliberately infected a lab worker with the virus. In The Real Anthony Fauci, he endorses a different theory, writing that the virus “entered polio vaccines at the Walter Reed Hospital laboratories in 1955” and caused a “devastating pandemic.” It’s part of his absurd argument that polio vaccines caused more harm than the potentially paralytic disease itself.
In fact, RSV’s discovery did begin in a laboratory, with chimpanzees getting the sniffles. In October 1955, 14 chimps housed at an annex of the Walter Reed Army Institute of Research in Silver Spring, Maryland, all came down with what seemed like a cold. Scientists set about determining what made them sick, swabbing their throats and taking blood samples. Researchers isolated the virus and intentionally infected another group of chimps. In February 1956, a lab worker who had contact with the second group of chimps fell ill. Tests indicated that the worker and the chimps had the same virus.
If that were all you knew, you might think Kennedy was onto something: Chimps get sick, a lab worker catches it, and a novel pathogen is thereby unleashed on humanity. It’s a compelling story and one that supports Kennedy’s thesis that scientists, rather than diligently searching for the cures to what ails us, are courting disaster with their reckless experiments.
But the real story doesn’t end there. Evidence soon emerged that RSV had been circulating in humans long before it was found at Walter Reed. In 1957, researchers at Johns Hopkins University reported that 80 percent of the children they had tested in Baltimore had antibodies to the virus by age 4. Inmates at a federal prison in Ohio had antibodies too. Those findings strongly suggested widespread, long-standing human infection rather than a virus suddenly escaping from a chimp colony. The Johns Hopkins scientists surmised that the virus might be of human origin and had been “introduced into a susceptible population of chimpanzees.”
More solid proof of that hypothesis came decades later. A study published in 2007 detected RSV proteins in preserved lung tissue from a child who died in 1931, nearly a quarter century before the chimp outbreak. The authors called it “the earliest confirmed case of RSV infection ever reported.” Other evidence points back even earlier. Descriptions of an illness researchers believe was likely RSV can be found in accounts from the 19th century. An 1819 treatise refers to an “acute suffocative catarrh”—that is, a thick buildup of mucus—that matches RSV’s characteristic symptoms. A recent analysis of genetic changes in RSV estimated that ancestors of today’s virus have been circulating for hundreds of years.
I spoke with several RSV researchers about Kennedy’s theory. None of them gave it any credence, including Philip Roane, who was a technician at Johns Hopkins in the mid-1950s and helped identify the virus in children. (Roane, who is now 98 and a microbiology professor at Howard University, wasn’t given formal credit on the 1957 paper, but he received a box of chocolates and a bottle of scotch from the lead author.) When I told Larry Anderson, a professor emeritus of infectious diseases at Emory University and a longtime RSV researcher, what Kennedy had said, I had to wait until he stopped laughing to get his answer. This isn’t a theory that researchers I spoke with—some of whom have spent decades studying RSV—take seriously.
But Kennedy still had to get that theory from somewhere, right? In The Real Anthony Fauci, Kennedy cites a 2021 article, “From Chimpanzees to Children: The Origins of RSV,” by Lyn Redwood. The relationship between Kennedy and Redwood, a nurse practitioner and anti-vaccine activist, goes back to 2005: Redwood, who believes that her son’s autism was caused by exposure to a mercury-based preservative in vaccines, was among a group of activists looking to recruit prominent figures to support their cause. Kennedy credits her with helping persuade him to take on the issue of vaccine safety.
In her article, Redwood, who is now a senior adviser to the health secretary, suggests that RSV-infected cells from Walter Reed chimpanzees might somehow have made it into the polio vaccine. The tainted vaccine, in turn, could have infected millions of children who received it in the 1950s. But that speculation rests on an obvious error: The kidney cells used to produce early polio vaccines came from monkeys, not chimpanzees. Redwood conflates the two in her article, referring to the chimps at Walter Reed as “sick monkeys.” When I contacted Redwood recently, she defended her article, saying she did not believe the evidence that RSV had been circulating among humans before 1956, even after I sent her the paper about the 1931 tissue sample. (She didn’t respond to an email noting the monkey mistake.)
As for whether RSV made it into the polio vaccine, she told me that she “just posed the question” and that anyone who claimed otherwise would be “misrepresenting my article.” In his book, Kennedy does precisely that: He cites her article when he writes that the virus spread via polio vaccines. What began as confused conjecture by Redwood was repackaged by Kennedy as simple fact.
When I asked HHS for clarification on Kennedy’s views, a spokesperson told me in an email that RSV “originated from a troop of infected chimpanzees,” and that the virus “spread to lab workers and then to the public but not through vaccination.” None of that is true—and it contradicts the (also false) account in Kennedy’s book. When it comes to rewriting medical history, the health secretary can’t even keep his fictions straight.