Measles Is Harmful, Contrary to Flimsy Social Media Claims of Long-Term Benefits – FactCheck.org

SciCheck Digest

Measles is an extremely contagious vaccine-preventable disease that can lead to death or disability. It also wipes out immune memory for several years after an infection. As an outbreak in Texas continues to expand, social media posts have claimed without sufficient support that measles infections are beneficial later in life against cancer and other diseases, an idea health secretary Robert F. Kennedy Jr. has echoed.

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Measles is one of the most contagious diseases and can be safely prevented with two doses of the measles, mumps and rubella, or MMR, vaccine. 

The viral disease causes a high fever, rash and other symptoms. Although most cases aren’t serious, even patients with mild disease are miserable, and there is a relatively high rate of complications and death. 

For every 1,000 children who contract measles, around 1 to 3 will die, often from pneumonia, according to the Centers for Disease Control and Prevention; 1 in 1,000 will develop encephalitis, or swelling of the brain, which can lead to permanent hearing loss or intellectual disability. About a fifth of unvaccinated patients require hospitalization.

Even if someone appears to recover unscathed, research shows the infection has negative effects on the immune system that can make people more susceptible to other illnesses for several years afterward.

There isn’t good evidence that a measles infection provides protection against various chronic illnesses when a person is older. But as a measles outbreak in Texas that began in January continues to grow, social media posts have been touting alleged benefits of the infection while failing to mention the clear and established harms.

“There are notable long-term health benefits associated with having had the measles,” declared one Instagram post last month. 

“When you realize wild measles will protect you against cancer, you understand why the industry wants to prevent that,” another Instagram post, from March 11, reads.

As of March 14, the measles outbreak in Texas, which is centered on undervaccinated communities in the western part of the state, has grown to 259 cases, including 34 hospitalizations and one death. Neighboring New Mexico has reported 35 cases, including two hospitalizations and one individual who tested positive after death.

In a video clip posted to X on Feb. 24, Mary Holland, the CEO of the anti-vaccine advocacy group Children’s Health Defense, said, “There are some real benefits from training your immune system against measles, and they’re very well documented. People who have had measles have lower rates of certain types of cancers, they have lower rates of other kinds of illnesses going forward in life.”

Holland cited an article her organization had recently republished by Sayer Ji. Ji, the founder of an alternative medicine website, has previously spread false and misleading health claims online. In 2021, he was listed as number eight on the Center for Countering Digital Hate‘s “Disinformation Dozen,” a roster of the 12 most influential spreaders of anti-vaccine content on social media.

Robert F. Kennedy Jr., the founder and former chairman of Children’s Health Defense who is now the Department of Health and Human Services secretary, has made similar comments.

“There’s a lot of studies out there that show that if you actually do get the wild infection, you’re protected later. It boosts your immune system later in life against cancers, atopic diseases, cardiac disease, et cetera,” he said of measles in a Fox News interview earlier this month. 

Kennedy acknowledged that it’s “not well studied,” but said it should be “because we ought to understand those relationships.”

In a 2023 interview with the libertarian magazine Reason, Kennedy also claimed there were “lots and lots” of studies showing measles infection in childhood provides “heightened immunity against certain kinds of cancers, against ectopic disease, against cardiac disease and allergic disease when you get older.”

Speaking of childhood infections such as measles, he added, “It immunizes you and it builds your immune response in the future against all kinds of really bad diseases that actually kill you.”

HHS hasn’t responded to our inquiry about Kennedy’s comments. 

Measles Harms the Immune System

“There is no good data to demonstrate that measles improved health,” Dr. Michael Mina, a former professor at Harvard School of Public Health who has studied measles and its effects on the immune system, told us. “We’ve shown precisely the opposite.”

In a series of papers first published a decade ago, Mina and colleagues found that in addition to a short period of profound immunosuppression immediately after a measles infection, there is a longer-term harmful effect on the immune system. 

According to this work, the measles virus can kill off many of the body’s memory immune cells, causing the immune system to “forget” past infections and erasing much of a person’s preexisting immunity. This so-called immunological amnesia makes measles survivors susceptible to infections they previously would have been protected against. The effects can last for as many as five years after a bout of measles as individuals slowly reacquire the immunity they lost.

The findings help explain why the introduction of the measles vaccine has reduced overall childhood mortality from infectious diseases by as much as 50% or more — far more than by preventing measles deaths alone.

“We only see adversity as a result of measles,” Mina said.

Measles, then, hardly “boosts” the immune system, as Kennedy said.

There are a few observational studies that suggest measles infections could be associated with fewer allergic diseases. But these studies, which are often small or rely on self reports of past measles infection, demonstrate associations, not causal relationships. 

Mina said it was “hard to make much” of that data, given the other differences that might exist in the people who did versus didn’t report a previous measles infection.

Notably, there are also studies that contradict these findings — or suggest that the MMR vaccination might also be linked to fewer allergic diseases. A study published in JAMA in 2000, for example, which included more than 500,000 children in Finland, found that children who experienced measles infections were more likely to have eczema, rhinitis or asthma. 

Contrary to suggestions that vaccination might increase allergic conditions by removing measles as an exposure, a 2021 systematic review found “no evidence” of an association between the MMR vaccine and asthma, dermatitis/eczema or hay fever.

As other fact-checkers have detailed, there are some papers that claim to find a link between measles infection or other childhood diseases and fewer cancers. But these findings are at best preliminary — and have not been consistent. One 2013 paper concluded that “further studies are required to confirm the specific associations identified, particularly given the current lack [of] consensus within the literature.” 

One of the papers cited in one of the Instagram posts used a questionnaire to determine past childhood infections and did not control for any other factors that might have influenced whether a person develops cancer. It was published in a dubious journal by anthroposophic doctors, who use alternative medical treatments, and was not peer-reviewed.

As for heart disease, there is a 2015 paper from Japan that reported finding an association between measles and mumps infections and a lower risk of death from atherosclerotic heart disease. The study, however, relied on participants to recall those infections and was conducted in a pre-vaccine population that was not vaccinated. It’s unclear how reliable the results are, as virtually all children of that era would have contracted measles.

Many of these studies propose that the so-called hygiene hypothesis, which contends that children need exposures to microbes early in life to train the immune system how to respond, could explain these associations. But Mina said that doesn’t make sense.

“We get exposed and infected with things that drive those same responses all the time,” he said. “Measles is literally the smallest drop in the bucket of our antigenic exposures.”

Not only is the measles virus just one of trillions of microbes a person would encounter, but because the measles vaccine is a weakened form of the virus, people who are vaccinated would still be receiving that exposure.

“You’re literally giving people all of the exposures to the proteins that they would get if they got an actual viral infection, only it’s much more controlled,” Mina said. “The hygiene hypothesis just really doesn’t fit.” 

Precisely because of measles’ unique ability to damage the immune system, it’s possible a measles infection could wipe out cancer- or autoimmune-causing cells, resolving those conditions. There are rare case reports of such occurrences. But that is different from a measles infection preventing those diseases later in life.

“That’s really, really remote,” Mina said, adding that even in those cases, the benefit would never outweigh the risk of getting measles.

Indeed, even if there are a few potential benefits to a measles infection, the downsides of the infection are abundantly clear and well established. Claims that suggest people would be better off getting a measles infection rather than a vaccine are incorrect.

Correction, March 14: We mistakenly wrote that Mina had said the risk of getting measles would never outweigh the benefit, instead of the other way around. We fixed the error.

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