On Wednesday, I flew home from a work trip and immediately jumped in the shower. Why? Because I needed to wash “the plane” off me. That’s also why I packed alcohol wipes for my tray table and armrests, why I wore a mask during boarding, deplaning, and most of the flight (except when sipping my ginger ale, which somehow tastes better in the air), and why I wash my hands diligently after touching any public surface. I have also received all vaccines available to me.

Emory research shows that window seats cut your contact with potentially sick passengers significantly. But I choose aisle seats anyway. My post-baby bladder means I’m getting up frequently, and I’d rather not climb over strangers (which introduces other exposures and uncomfortable interactions). This is exactly why we need multiple layers of protection—because the “ideal” choice isn’t always possible.

So when Secretary Kennedy’s Instagram video about sanitation being the real hero of public health started flooding my inbox, I watched it carefully. He makes specific claims that deserve examination, especially given the timing—shortly after his administration pointed to Tylenol rather than vaccines as a potential autism cause, disappointing many who expected a different announcement. Let’s discuss...

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The Challenge of Measuring What Never Happened

As a data person, I spend my days trying to tease apart cause and effect. In public health, this is particularly tricky. How do you count the children who didn’t get sick? The epidemics that didn’t spread? We can’t run controlled experiments where half a city gets clean water and half doesn’t. Instead, we piece together evidence from natural experiments and from observational studies, looking for patterns in the noise.

Kennedy’s video ignores this complexity, presenting selective data as the complete story. So, what is he leaving out?

Kennedy’s Claim: The 70% Mortality Decline

Kennedy correctly states that infectious disease mortality dropped 70% in the early 20th century, before most vaccines. He’s right. Historical records show that in 1900, life expectancy at birth was just 47 years. Cities were cesspools: open sewage, contaminated water, garbage literally feet deep in streets. Can you imagine the stench? The sanitation revolution—clean water, sewage treatment, refrigeration, pasteurization—was transformative. By 1953, life expectancy at birth had jumped to 69 years.

But Kennedy presents sanitation as the explanation. In reality, multiple forces were at play: improved nutrition, better housing, labor laws, discovery of vitamins, and by the 1940s, antibiotics. After 1950, the picture changed dramatically—that’s when vaccines and modern medicine took the lead.

Kennedy’s Claim: Diseases Were Already Disappearing

Kennedy shows graphs where measles deaths drop from around 13,000 annually at the turn of the 20th century to a few hundred by 1960, before the vaccine in 1963. He’s technically right on deaths—but not on disease.

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CDC records show 3-4 million measles cases every single year in the decade before the vaccine. Nearly every American child still got measles. Many suffered lifelong complications: deafness, encephalitis, immune system damage. Deaths dropped because of better hospitals—oxygen support, antibiotics for secondary infections—not because the virus had faded.

The same pattern held for other transmissible diseases. Polio paralyzed 21,000 children in 1952. Rubella caused 20,000 birth defects in the 1964-65 outbreak. Whooping cough still killed thousands annually. These diseases spread regardless of sanitation improvements.

When vaccines arrived, the game changed. Measles cases plummeted 99% after 1963. Polio was eliminated by 1979. Hib meningitis—20,000 cases annually before 1987—virtually disappeared within a decade. Not deaths. Cases. The diseases themselves nearly vanished.

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When Sanitation Met Its Match: The 1904 Connecticut Lesson

Kennedy’s narrative assumes sanitation and quarantine could control airborne diseases. History says otherwise. In 1904, Connecticut’s health secretary C.A. Lindsley desperately tried to control measles epidemics through strict quarantine. Despite posting signs threatening fines and imprisonment, measles kept spiraling “out of control across the state.”

Why? Because many still viewed measles as “a disease of small moment”—not worth strict enforcement. Sound familiar? Between 1900-1910, measles killed an average of 774 Americans annually. Yet even with visible death tolls and quarantine signs on doors, communities couldn’t contain an airborne virus that spreads before symptoms appear.

The Smithsonian archives note that quarantines worked better in wealthy neighborhoods with single-family homes but failed in crowded tenements—another reminder that public health interventions always have gaps based on social conditions. This was during the exact period Kennedy celebrates for sanitation improvements. Clean water couldn’t stop what traveled through the air.

Kennedy’s Claim: CDC Study Shows Vaccines Deserve “Little Credit”

Kennedy cites a 2000 CDC/Johns Hopkins study by Guyer and colleagues claiming it shows vaccines deserve “little credit.” But he strips its conclusion out of context. The study states: “Thus vaccination does not account for the impressive declines in mortality seen in the first half of the century.”

The first half. Before 1950. When there were few vaccines.

Indeed, Guyer’s review of the entire century’s data confirms this pattern. Between 1900 and 1998, infectious diseases’ share of childhood deaths dropped from 61.6% to just 2%. The study explicitly credits post-1950 medical advances—including vaccines—for “nearly eliminating” deaths from vaccine-preventable diseases like diphtheria, pertussis, and polio. The authors note that “the decline in infant mortality received new momentum in the 1960s,” specifically due to medical interventions, not sanitation improvements. They confirm that “The reductions in vaccine-preventable diseases are impressive.... Deaths from [diphtheria, pertussis, and measles] have been virtually eliminated, as have deaths from Haemophilus influenzae, tetanus, and poliomyelitis.”

Kennedy uses a study that actually supports vaccination to argue against it.

Kennedy’s Claim: The McKinlay Study Proves His Point

Kennedy’s video relies heavily on the McKinlay & McKinlay 1977 study, repeatedly citing their finding that medical measures contributed at most 3.5% to mortality decline before 1950. What he doesn’t mention? The McKinlays themselves explicitly reject anti-vaccine interpretations of their work.

In 2020, when reflecting on how anti-vaccine advocates misuse their research, the McKinlays stated: “We consider this an egregious misinterpretation of our resear