Posted by Katherine J. Wu

https://www.theatlantic.com/health/2025/11/nih-pandemic-miasma/684979/?utm_source=feed

Last week, the two top officials at the National Institutes of Health—the world’s largest public funder of biomedical research—debuted a new plan to help Americans weather the next pandemic: getting everyone to eat better and exercise.

The standard pandemic-preparedness playbook “has failed catastrophically,” NIH Director Jay Bhattacharya and NIH Principal Deputy Director Matthew J. Memoli wrote in City Journal, a magazine and website published by the Manhattan Institute for Policy Research, a conservative think tank. The pair argue that finding and studying pathogens that could cause outbreaks, then stockpiling vaccines against them, is a waste of money. Instead, they say, the United States should encourage people to improve their baseline health—“whether simply by stopping smoking, controlling hypertension or diabetes, or getting up and walking more.”

On its own, Bhattacharya and Memoli’s apparently serious suggestion that just being in better shape will carry the U.S. through an infectious crisis is reckless, experts told me—especially if it’s executed at the expense of other public-health responses. In an email, Andrew Nixon, the director of communications at the Department of Health and Human Services—which oversees the NIH—wrote that the agency “supports a comprehensive approach to pandemic preparedness that recognizes the importance of both biomedical tools and the factors individuals can control.” But more broadly, Bhattacharya and Memoli’s proposal reflects the spread of a dangerous philosophy that Robert F. Kennedy Jr., the secretary of HHS, has been pushing for years: a dismissal of germ theory, or the notion that infectious microbes are responsible for many of the diseases that plague humankind.

In his 2021 book, The Real Anthony Fauci: Bill Gates, Big Pharma, and the Global War on Democracy and Public Health, Kennedy, a longtime anti-vaccine activist, argues that modern scientists have blamed too much of infectious disease on pathogens, which he suggests are rarely problematic, unless the immune system has been compromised by poor nutrition, toxins, and other environmental stressors. He credits sanitation and nutrition for driving declines in infectious-disease deaths during the 20th century; vaccination, he has baselessly claimed, was largely ineffective and unnecessary. In his view, germs don’t pose a substantial threat to people who have done the work of “fortifying the immune system”—essentially, those who have taken their health into their own hands.

In terms of general health, most Americans would benefit from improvements in diet and exercise. A strong emphasis on both has been core to the Make America Healthy Again movement, and in one important aspect, Kennedy and his allies are correct: The immune system, like other bodily systems, is sensitive to nutritional status, and when people are dealing with chronic health issues, they often fare less well against infectious threats, Melinda Beck, a nutrition and infectious-disease researcher who recently retired from the University of North Carolina, told me. Conditions such as obesity and diabetes, for instance, raise the risk of severe COVID and flu; malnutrition exacerbates the course of diseases such as tuberculosis and measles.

But applied to widespread infectious outbreaks, the MAHA prescription is still deeply flawed. Being generally healthy doesn’t guarantee survival, or even better outcomes against infectious diseases—especially when an entire population encounters a pathogen against which it has no immunity. Although some evidence suggests that the 1918 flu pandemic strongly affected certain groups of people who were less healthy at baseline—including undernourished World War I soldiers—“relatively healthy people, as far as we could understand, were the main victims,” Naomi Rogers, a historian of medicine at Yale, told me. Smallpox, too, infected and killed indiscriminately. HIV has devastated many communities of young, healthy people.

In his book, Kennedy relies heavily on the term miasma theory as a shorthand for preventing disease “through nutrition and by reducing exposures to environmental toxins and stresses.” He’s employing that phrase incorrectly: Historically, at least, miasma theory referred to the notion that epidemics are caused by bad air—such as toxic emanations from corpses and trash—and was the predominant way of describing disease transmission until scientists found definitive proof of infectious microbes in the late 19th century. But his choice of words is also revealing. In pitting his ideas against germ theory, he plays on a centuries-old tension between lifestyle and microbes as roots of illness.

In its early days, germ theory struggled to gain traction even among physicians, many of whom dismissed the idea as simplistic, Nancy Tomes, a historian at Stony Brook University, told me. After the idea became foundational to medicine, scientists still had to work to convince some members of the public that microbes could fell healthy people, too. In the early days of polio vaccination, when the virus still ran rampant in the U.S., some vaccine-skeptical Americans insisted that children were falling seriously ill primarily because their parents weren’t managing their kids’ nutrition well and “had disrupted the child’s internal health,” Rogers told me.

Over time, as pharmaceutical companies made global businesses out of selling antibiotics, vaccines, and antivirals, the products became a symbol, for some people, of how germ theory had taken over medicine. Accepting vaccines came to represent trust in scientific expertise, Rogers said; misgivings about the industry, in contrast, might translate into rejecting those offerings. In that skeptical slice of the American public and amid the rise of alternative-wellness practitioners, Kennedy has found purchase for his ideas about nutrition as a cure-all.

Since taking over as health secretary, he has on occasion made that distrust in germ theory national policy. In his book, he wrote that “when a starving African child succumbs to measles, the miasmist attributes the death to malnutrition; germ theory proponents (a.k.a. virologists) blame the virus.” Earlier this year, when measles raged through undervaccinated regions of West Texas, the secretary acted out his own miasmist theory of the outbreak, urging Americans to rely on vitamin-A supplementation as a first-line defense, even though deficiency of that vitamin is rare here.

But germ theory is key to understanding why outbreaks become pandemics—not because people’s general health is wanting, but because a pathogen is so unfamiliar to so many people’s immune systems at once that it is able to spread unchecked. Pandemics then end because enough people acquire sufficient immunity to that pathogen. Vaccination, when available, remains the safest way to gain that immunity—and, unlike lifestyle choices, it can represent a near-universal strategy to shore up defenses against disease. Not all of the risk factors that worsen disease severity are tunable by simply eating better or working out more. For COVID and many other respiratory diseases, for instance, old age and pregnancy remain some of the biggest risk factors. Genetic predispositions to certain medical conditions, or structural barriers to changing health habits—not just lack of willpower—can make people vulnerable to disease, too.

In their article, Bhattacharya and Memoli purport to be arguing against specific strategies of pandemic preparedness, most prominently the controversial type of gain-of-function research that can involve altering the disease-causing traits of pathogens, and has been restricted by the Trump administration. But the pair also mischaracterize the country’s current approach to pandemics, which, in addition to calling for virus research and vaccine development, prioritizes measures such as surveillance, international partnerships, and improved health-care capacity, Nahid Bhadelia, the director of the Center on Emerging Infectious Diseases at Boston University, told me. And Bhattacharya and Memoli’s alternative approach cuts against the most basic logic of public health—that the clearest way to help keep a whole population healthy is to offer protections that work on a societal level and that will reach as many people as possible. Fixating on personal nutrition and exercise regimens as pandemic preparedness would leave many people entirely unprotected. At the same time, “we’re basically setting up society to blame someone” in the event that they fall ill, Jennifer Nuzzo, the director of the pandemic center at the Brown University School of Public Health, told me.

Kennedy’s book bemoans that the “warring philosophies” of miasma and germ theory have become a zero-sum game. And yet, at HHS, he and his officials are presenting outbreak preparedness—and the rest of public health—as exactly that: The country should worry about environment or pathogens; it should be either pushing people to eat better or stockpiling vaccines. Over email, Nixon told me that “encouraging healthier habits is one way to strengthen resilience alongside vaccines, treatments, and diagnostics developed through NIH-funded research.” But this year, under pressure from the Trump administration, the NIH has cut funding to hundreds of vaccine- and infectious-disease focused research projects; elsewhere at HHS, officials canceled nearly half a billion dollars’ worth of contracts geared toward developing mRNA vaccines.

The reality is that both environment and pathogens often influence the outcome of disease, and both should be addressed. Today’s public-health establishment might not subscribe to the 19th-century version of miasma theory, but the idea that environmental and social factors shape people’s health is still core to the field. “They’re saying you can only do one thing at a time,” Bhadelia told me. “I don’t think we have to.”

https://www.theatlantic.com/health/2025/11/nih-pandemic-miasma/684979/?utm_source=feed