America has made measles great again. Not even halfway into 2026, the nation is already poised to surpass last year’s record-setting number of confirmed measles cases, judging from the latest data out of the U.S. Centers for Disease Control and Prevention (CDC).
But this seemingly headlong race to end America’s herd immunity to measles—a disease that had spent most of the 21st century officially eliminated within its borders—is really only just the beginning of the problem. Adding insult to injury, new research published in the Journal of the American Medical Association’s JAMA Network Open has shown a troubling rise in public engagement with some notably ineffective and potentially toxic alternative treatments for this deadly and highly contagious disease.
The researchers used Google search trend data from January to June 2025 to quantify public interest in the topic. They then compared changes in online interest with a timeline of media coverage and public statements from Trump administration officials across multiple agencies.
The researchers detected two fascinating (albeit alarming) surges in interest. The first occurred in the wake of a March 4, 2025, Fox News interview with Trump’s Health and Human Services Secretary Robert F. Kennedy Jr. During the interview, the infamous anti-vaxxer touted cod liver oil supplements and vitamin A as viable treatments for measles. A second series of spikes surrounded two late March podcast appearances by certified physician and noted vaccine skeptic Suzanne Humphries, who promoted the same two questionable remedies. Neither of Humphries’ interviews involved a government official, but one did occur on the chart-topping podcast of Joe Rogan.
“Between January [1] and March [31,] 2025, America’s Poison Centers reported a 38.7% increase in vitamin A exposures,” the new study noted, citing data published by the poison center about 12 days after Humphries’ appearance on Rogan.
‘Unclear’ guidance
The study’s authors, researchers with Harvard Medical School and elsewhere, worked to quantify the reach of the media and government statements touting these treatments, before gauging them against search queries like “‘vitamin A’ measles children” and “‘cod liver’ measles.” To reduce bias in its comparisons, the team employed statistical tools—including the open-source software PersistAD—to “differentiate persistent shifts from routine fluctuations” in this Google Trends data.
The spikes in interest they recorded “coincided with multiple media statements,” they wrote. Vitamin A interest, in particular, proved to be a mean 7.5% higher than the researchers’ predicted counterfactual estimates.
“Our findings underscore media’s influence on health-seeking behavior during public health emergencies like the measles outbreak,” the researchers noted, “which is particularly concerning when guidance from trusted sources is unclear and may encourage detrimental behaviors.”
Fish oil
Before these recent years of politicized debate around vaccines, the once traditional measles, mumps, and rubella (MMR) vaccine proved uncontroversial and well-regarded given its proven 97% protection rate. The same was true of tandem nutritional supplements, as judiciously recommended by medical professionals.
“Vitamin A may be administered under medical supervision to support measles recovery, but it does not prevent measles and can be toxic if dosed incorrectly,” the researchers noted in their study. “The same applies to cod liver oil, which contains high levels of vitamin A.”
As previous research notes, vitamin A can be toxic because of the way our bodies efficiently store it, allowing it to accumulate in the liver and other tissues, where high levels can damage organs and bones. According to the Mayo Clinic, excessive vitamin A intake (more than 10,000 mcg per day) can result in balance issues, liver damage, headaches, nausea, and other conditions.
But acknowledgment of those subtle dangers was notably absent in Rogan’s interview with Humphries: “If you get an infection with measles, just a natural infection, or if you get the vaccine, you’re still going to get depleted of vitamin A. Like, if you get vaccinated for measles, you should be taking vitamin A,” Rogan said, parroting Humphries’ book back to her. (“That’s right,” Humphries chimed in.)
“There’s real science behind all the things you talk about in your book,” Rogan added later, citing “vitamin A and cod liver oil, which also has vitamin A.” In some ways, his words of encouragement were not entirely dissimilar from Rogan’s prior hosting duties on the NBC reality competition Fear Factor, wherein he once goaded a man into drinking a smoothie of cod liver oil, rooster testicles, and bile.
In an Instagram post promoting the podcast episode, Rogan called Humphries “a very brave and brilliant woman” whose writing had changed his perspective on vaccine history. From one avid reader to another, I hope you’re reading this now, Joe.
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