Occasionally, someone in government policymaking dusts off an ancient idea so thoroughly mothballed you’d half expect it to come with a whiff of old books. In this case, it’s Health and Human Services Secretary Robert F. Kennedy Jr., who, as NPR reports, appears to be channeling the centuries-old “miasma theory”—the belief that noxious air, rather than invisible germs, is the culprit behind disease. This peculiar bit of historical nostalgia may help explain some of his more eyebrow-raising vaccine stances.

Revisiting What’s in the Air

The miasma theory is about as retro as it gets in medical history. As described by NPR and echoed in coverage by Voice of Alexandria, thinkers from ancient Greece—Hippocrates among them—proposed that some sort of atmospheric pollution, especially stink from decaying things, was to blame for epidemics. Florence Nightingale herself once lobbied for cleaner air and hospitals using this logic, and it led, perhaps incidentally, to sanitation wins like better sewage systems. As Dr. Howard Markel, a medical historian interviewed by Rob Stein for NPR, points out, the idea was “epidemics came from some type of pollution – some pollution of the atmosphere.”

Of course, this all took a sharp turn with germ theory. Researchers like Louis Pasteur and Robert Koch changed the game entirely by showing it’s not the smell, but the tiny critters—bacteria and viruses—carried in air, water, and handshake alike. According to Melanie Kiechle, a historian quoted in NPR’s segment, “bacteria and viruses and other microscopic materials were actually what caused illness and also explained the spread of illness from one person to another.” Suddenly, the villain wasn’t an unidentified miasma, but something you might spot under a microscope after a few rounds with fluorescent dye.

Kennedy’s Vintage Approach

It wouldn’t be a week in American public health without a Kennedy headline, but this one is a throwback even by those standards. In his 2021 book The Real Anthony Fauci: Bill Gates, Big Pharma, and the Global War on Democracy and Public Health, Kennedy draws on miasma theory as a guiding lens, writing about preventing disease “by fortifying the immune system through nutrition and reducing exposures to environmental toxins and stresses,” as cited in NPR’s report. His policies, including vaccine skepticism, seem to mirror this idea—attributing modern maladies to a kind of high-tech pollution.

The Voice of Alexandria summarizes this move succinctly: Kennedy “apparently embraces the outdated ‘miasma theory’ of disease instead of the widely accept[ed] ‘germ theory’ of disease, which may help explain some of the actions he’s been taking.” Evidently, for Kennedy, the contemporary miasma isn’t lingering fog over a medieval city, but electromagnetic fields, pesticides, and, perplexingly, vaccines themselves—a position outlined by Dr. Paul Offit, a vaccine expert quoted in NPR, who describes Kennedy’s perspective as classifying these environmental factors as modern poisons.

What Do the Experts Say?

Historians and public health professionals seem largely united—if not outright exasperated—on this point. Nancy Tomes, author and historian interviewed by NPR, states outright that Kennedy’s repackaging of miasma theory doesn’t square with any historical definition of the term. Dr. Tina Tan, head of the Infectious Disease Society of America, tells NPR that, while factors like air pollution can make infections worse, “the cause of infections is a microorganism. It’s the microorganisms that are making people sick.”

Adding to the consensus, Dr. Amesh Adalja from the Johns Hopkins Center for Health Security remarks to NPR that invoking miasma in this way is simply “obfuscation to support his idea that vaccines are not valuable,” giving such views a “false veneer of intellectualism.” There’s a certain poetry to couching contemporary positions in centuries-old medical theory—though not, perhaps, the type of poetry that would pass peer review.

Interestingly, there are voices trying to temper the friction. As Gregg Girvan, a policy fellow cited by NPR, observes, “The real debate here is whether we can solve public health problems by developing treatments like vaccines, antibiotics, or other drugs? Or whether we will solve these problems by strengthening people’s immune systems through healthier habits? And my response is, ‘Why can we not acknowledge that there is truth in both positions?’” Food for thought—or perhaps more accurately, a question best served with a side of scientific rigor.

The Past Isn’t Even Past

It’s worth wondering: if we’ve gone back to miasma theory, should we also bring back leech therapy and four humours for the full set? There’s a certain fascination in watching ancient ideas whir back to life among modern policymakers, especially when the historical version—bad smells cause illness—has been debunked longer than Coca-Cola has existed. Yet, as Voice of Alexandria and NPR both document, here it is again: the ghost of public health’s past, peeking through the keyhole.

Maybe it’s a reminder that the line between productive skepticism and willful disregard for evidence can get a little foggy, especially when the air is thick with metaphor—if not actual miasma. One wonders what Hippocrates would have made of Wi-Fi routers. Or what Florence Nightingale might’ve said about “toxic vibes” from your phone.

For now, public health experts seem decidedly unmoved by the renaissance of ancient airs and humours. It’s a strange little chapter in the long, winding saga of people trying to explain why we get sick. In the end, it appears that neither history, nor science, nor one’s nose, is quite prepared to hand modern medicine back over to the whims of the wind. But this is, if nothing else, a reminder: leave a window open too long, and you never know what type of drafty old theory might blow back in.