As a measles outbreak sweeps through Texas, officially sickening 124 people, mostly unvaccinated children, and hospitalizing 18, anti-vaccine groups are pushing a familiar and false theory: The highly contagious virus is being caused by the vaccine itself.
“The narrative is that it’s a failure to vaccinate when we know it is a failing vaccine,” said Sayer Ji, a self-described natural health and wellness thought leader who is not a doctor. He outlined his theory Monday during an interview on the internet morning show from Children’s Health Defense, an anti-vaccine nonprofit formerly led by Robert F. Kennedy Jr., who resigned after being chosen by President Donald Trump to run the Department of Health and Human Services.
Ji’s discussion with Children’s Health Defense’s director of programming, Polly Tommey, comes as Texas health authorities work to contain an outbreak of one of the world’s most contagious diseases, in part through a campaign to vaccinate residents. The measles, mumps and rubella (MMR) shot is remarkably safe and effective, experts said, and the mild reaction that some people experience after receiving it is unlikely to be confused with measles.
But that has not stopped Ji, Tommey and a growing chorus of state “health freedom” groups and conspiracy theory websites from pushing the false claims. They’ve also argued the U.S. Centers for Disease Control and Prevention should be testing to determine the difference between these theorized vaccine-caused cases and naturally occurring wild-type measles. And they’ve suggested the tests weren’t being done as part of a wider conspiracy or “psychological operation” against Kennedy.
“It is no coincidence in my mind that Bobby gets confirmed to be secretary of HHS, and immediately we have a measles outbreak,” said Tommey, who is the mother of an adult child whom she says was injured by the MMR vaccine. “Parent to parent, do not go anywhere near that vaccine.”
In fact, the Texas Department of State Health Services is genotype testing measles samples for surveillance purposes. All samples tested in the outbreak have come back as genotype D8, a known strain of the wild measles viruses — not the vaccine, said Lara Anton, senior press officer at the department.
Testing “helps us determine if cases are related” to each other, Anton said. “It also helps us know whether a positive measles test for someone who was recently immunized is due to an actual infection or to a reaction to the vaccine.”
The fears about the measles vaccine are ungrounded, said Dr. Matthew Washam, director of epidemiology at Nationwide Children’s Hospital in Ohio who co-authored a paper about vaccine shedding — when a vaccine releases parts of a virus, stimulating an immune response, and sometimes causes symptoms of a disease, but not the disease itself. Ji inaccurately cited the paper on his blog as evidence for his unsupported theory.
“No, the MMR vaccine does not cause measles infection,” said Washam.
While an MMR vaccine can sometimes induce mild and temporary reactions such as a low-grade fever and rash, actual measles infections are more severe and can be deadly — they often come with high fevers, a full-body rash, ear infections, dehydration and pneumonia — and are linked to direct exposure, not the vaccine. It’s unlikely for the two to be confused, Washam said.
“This is a completely different phenomena,” Washam said. “It’s the body’s immune response to the vaccine. It’s not wild-type measles infection. Most importantly, it’s not transmissible to others, and it’s not a cause of an outbreak.”
There has never been a documented case of the MMR vaccine causing a measles infection that spread to others, Washam said, adding, “It’s an extremely great vaccine.”
He called the safety and efficacy of the measles vaccine “truly remarkable” and stressed its importance, especially for young children.
Though the symptoms for measles can sound mild, complications can be dangerous and even deadly. Out of every 1,000 cases, around 200 children require hospitalization, 50 develop pneumonia, one experiences brain swelling that can lead to deafness or disability, and between one and three die.
The theories espoused about Texas echo Kennedy’s false statements about the measles outbreak in Samoa in 2019. That fall, as young children were hospitalized and dying from measles infections, Kennedy wrote to the Pacific Island nation’s prime minister, warning about the possible danger of the vaccine campaign. “Nobody died in Samoa from measles,” he told an interviewer last August. “They were dying from a bad vaccine.”
Kennedy has not commented on the Texas outbreak since being confirmed as HHS secretary this month, but some of his early moves — including the shelving of planned ads for the flu vaccine and the postponement of a meeting of a vaccine advisory panel — have concerned public health experts.
He has previously downplayed the danger of measles, a common tactic of the anti-vaccine movement and a line of argument that Ji and Tommey repeated this week on the Children’s Health Defense show. They falsely theorized that the supposed vaccine measles strain was potentially more dangerous than so-called natural measles, which Ji said without evidence came with benefits to the immune system and reduced the risk of certain cancers.
For years, activists like Kennedy have suggested that the tens of thousands of children who were hospitalized and the hundreds who died each year from measles before vaccines were available are inconsequential when compared to the countless individuals who they claim — without evidence — have been harmed by the MMR vaccine. But when outbreaks occur, the narrative often shifts from minimizing measles to reviving the persistent anti-vaccine myth: that the MMR vaccine can shed and cause outbreaks.
Kennedy’s 2019 letter to Samoa’s leader referenced another outbreak, which started in California’s Disneyland in 2015 and spread to seven U.S. states, Mexico and Canada and sickened over 100 people. Kennedy claimed the outbreak was likely caused by vaccines — contrary to evidence that showed low vaccination rates as the culprit. The false theory seems to stem from a misreading of a California Department of Public Health report that mentioned cases of a vaccine-induced rash, not vaccine-induced measles.
HHS and the CDC did not respond to requests for comment. Tommey did not respond to requests for comment.
In an email, Ji disputed the experts’ opinions, calling them “an oversimplification that lacks conclusive scientific verification in the absence of proper genotyping,” and suggested a reporter consult a different report on vaccine shedding published by an anti-vaccine organization.
To Washam, the difference between measles and the MMR vaccine is the risk one is willing to take — especially for young children — to get immunity from measles.
“Were you given a very safe and effective MMR vaccine and therefore have immunity against measles?” he said. “Or did you have to survive wild-type infection, which can be a very severe infection, especially in young children?”
For now, the conspiracy theory appears confined to the internet and hasn’t yet taken root in the communities where measles is spreading, according to Dr. Ana Montanez, a pediatrician at Texas Tech Physicians in Lubbock who has treated several exposed families. Montanez said vaccine hesitancy there is currently driven by limited education, cultural isolation in the Mennonite community and a perceived lack of necessity.
“A lot of our parents are actually really open to asking questions,” she said. “It’s not misinformation about the vaccine causing outbreaks that’s the issue here. It’s more about, ‘Why should we vaccinate if we’ve never seen this disease?’”
