In a sweeping interview, Robert F. Kennedy Jr., the health and human services secretary, outlined a strategy for containing the measles outbreak in West Texas that strayed far from mainstream science, relying heavily on fringe theories about prevention and treatments.
He issued a muffled call for vaccinations in the affected community, but said the choice was a personal one. He suggested that measles vaccine injuries were more common than known, contrary to extensive research.
He asserted that natural immunity to measles, gained through infection, somehow also protected against cancer and heart disease, a claim not supported by research.
He cheered on questionable treatments like cod liver oil, and said that local doctors had achieved “almost miraculous and instantaneous” recoveries with steroids or antibiotics.
The worsening measles outbreak, which has largely spread through a Mennonite community in Gaines County, has infected nearly 200 people and killed a child, the first such death in the United States in 10 years.
Another suspected measles death has been reported in New Mexico, where cases have recently increased in a county that borders Gaines County.
The interview, which lasted 35 minutes, was posted online by Fox News last week, just before the President Trump’s address to Congress. Segments had been posted earlier, but the full version received little attention.
Mr. Kennedy offered conflicting public health messages as he tried to reconcile the government’s longstanding endorsement of vaccines with his own decades-long skepticism.
Vaccines are “recommended” for West Texans, but the risks of immunization have been underestimated, he said.
Mr. Kennedy acknowledged that vaccines “do prevent infection” and said that the federal government was helping ensure that people have access to “good medicines, including those who want them, to vaccines.”
“In highly unvaccinated communities like Mennonites, it’s something that we recommend,” he said.
Mr. Kennedy described vaccination as a personal choice that must be respected, then went on to raise frightening concerns about the safety of the vaccines.
He said he’d been told that a dozen Mennonite children had been injured by vaccines in Gaines County. People in the community wanted federal health workers arriving in Texas “to also look at our vaccine-injured kids and look them in the eye,” Mr. Kennedy said.
Yet the M.M.R. vaccine itself has been thoroughly studied and is safe. There is no link to autism, as the secretary has claimed in the past. While all vaccines have occasional adverse effects, health official worldwide have concluded that the benefits far outweigh the very small risks of vaccination.
Mr. Kennedy asserted otherwise: “We don’t know what the risk profile is for these products. We need to restore government trust. And we’re going to do that by telling the truth, and by doing rigorous science to understand both safety and efficacy issues.”
In response to questions about Mr. Kennedy’s position on vaccination, a Health and Human Services spokesman pointed to a recent opinion piece in which he wrote that the shots prevented children from contracting measles and protected people who couldn’t be vaccinated.
“However, he believes that ‘the decision to vaccinate is a personal one,’” the spokesman said, referring to Mr. Kennedy’s opinion article.
Mr. Kennedy claimed that it was “very difficult” for measles to kill a healthy person and that malnutrition played a role in the Texas outbreak.
Early in the interview, Mr. Kennedy acknowledged the seriousness of measles infection, noting that it can lead to death, brain swelling and pneumonia.
But he also described the illness as rarely fatal, even before 1963, when the vaccine became available. He said measles has a “very, very low infection fatality rate.”
According to the Centers for Disease Control and Prevention, for every thousand people infected with measles in the United States, the virus kills one to three. One study estimated that without vaccination today there would be 400,000 hospitalizations and 1,800 deaths annually.
Death isn’t the only possible consequence. Measles can also cause permanent blindness, deafness and intellectual disability. Before the vaccine became available, about a thousand people every year had encephalitis because of the virus.
In later comments, Mr. Kennedy suggested that severe symptoms mainly affected people who were unhealthy before contracting measles.
“It’s very, very difficult for measles to kill a healthy person,” he said, adding later that “we see a correlation between people who get hurt by measles and people who don’t have good nutrition or who don’t have a good exercise regimen.”
West Texas is “kind of a food desert,” he added. Malnutrition “may have been an issue” for the child who died of measles in Gaines County.
Texas health officials said the child had “no known underlying conditions.”
Dr. Wendell Parkey, a physician in Gaines County with many Mennonite patients, said the idea that the community was malnourished was mistaken.
Mennonites often avoid processed foods, raise their own livestock and make their own bread, he noted. From a very young age, many members of the community also help with farming and other physically demanding jobs.
“They’re the healthiest people out here,” he said. “Nutritionally, I would put them up against anybody.”
There is data to show that severely malnourished children in poor countries often suffer worse outcomes from measles, said Dr. Sean O’Leary, chair of the infectious disease committee at the American Academy of Pediatrics.
But there is no credible evidence that poor eating habits and exercise routines make a child more prone to measles complications, he added.
There is also ample evidence that measles routinely killed healthy children before the M.M.R. vaccine became available, said Patsy Stinchfield, immediate past president of the National Foundation for Infectious Diseases.
Before 1963, roughly 500 children, many of them previously healthy, died from the virus each year, she said. About 40 percent of people infected last year were hospitalized, according to the C.D.C.
In the interview, Mr. Kennedy appeared frustrated that a vaccine-preventable illness rather than chronic disease had drawn national attention during his first weeks as secretary.
“We’ve had two measles deaths in 20 years in this country — we have 100,000 autism diagnoses every year,” he said. “We need to keep our eye on the ball. Chronic disease is our enemy.”
The suggestion that vaccines cause autism has been discredited by dozens of scientific studies. Scientists have pointed out that measles deaths are so upsetting because they are preventable with vaccination.
“Natural immunity” after infection may protect the body against various chronic illnesses, the secretary said.
Asked whether he opposed so-called measles parties — events that parents hold to purposely spread measles from a sick child to healthy children — Mr. Kennedy said he would “never advise someone to get sick.”
But he also praised the benefits of natural immunity, protection gained after becoming infected with a virus, claiming that it lasted longer than vaccine-induced immunity and may later protect against cancers and cardiac disease.
While it’s true that a measles infection may offer lifelong protection against the virus, the risks of getting sick far outweigh any small immunity benefit, said Dr. O’Leary.
Two doses of the M.M.R. vaccine are about 97 percent effective at preventing an infection. Even if a vaccinated person gets a breakthrough infection, the illness tends to be mild.
Experts also said there was no credible evidence to support the claim that a measles infection protects against other diseases.
Just the opposite: A measles infection may cause “immune amnesia,” in which the body “forgets” how to defend itself against illnesses it has already been exposed to, making it more susceptible to future infections.
Kennedy spoke enthusiastically about unproven treatments for measles, and said the H.H.S. would study them.
Mr. Kennedy said the Department of Health and Human Services would conduct clinical trials on several unproven treatments for measles, including a steroid, budesonide; an antibiotic called clarithromycin; and cod liver oil, which he said was “the safest application of vitamin A.”
Mr. Kennedy said he had heard from two local doctors that these treatments had led to “miraculous and instantaneous recovery.”
“We need to really do a good job of talking to the frontline doctors and see what is working on the ground,” he said. “Those therapeutics have really been ignored by the agency for a long, long time.”
While physicians sometimes administer high doses of vitamin A to care for children with severe measles, delivering it via a dietary supplement like cod liver oil makes it difficult to administer precise amounts, said Dr. William Schaffner, an infectious disease specialist at Vanderbilt University Medical Center.
There is no credible data to suggest that cod liver oil is “in any way conceivably safer” than traditionally administered vitamin A, he added.
Dr. Schaffner said that antibiotics, which fight bacterial infections, are not effective treatments for measles, a virus. And he was unaware of any evidence that showed that steroids improved outcomes for children with measles.
Conducting a clinical trial of these treatments is difficult on a practical level — there are not enough children with measles in the United States to run a large trial. And such a study would be ethically fraught: Doctors might need to withhold standard supportive care, like vitamin A, in order to test these remedies.
Mr. Kennedy’s focus on unverified treatments has frustrated some doctors in Gaines County, who have been trying to explain to patients that there is no antiviral for measles and that they have little control over which patients suffer serious symptoms.
“We already are dealing with people that think measles is not a big deal,” said Dr. Leila Myrick, a family medicine doctor in Seminole, Texas, who has been caring for patients with measles for several weeks.
“Now they’re going to think they can get this miracle treatment and that they definitely don’t need to get vaccinated. It’s a 100 percent going to make it harder.”