Guardians of Human Flourishing: Infectious Disease Physicians

Pathogens are the obstacle. Human flourishing is the end.

Lately, I’ve been thinking deeply about what it means to be an infectious disease physician. Not the day-to-day work of managing drug-resistant bacteria, post-operative infections, or fevers in transplant patients, but the larger question beneath all of it. What exactly is the purpose of infectious disease medicine? What is its ultimate aim?

 First, every infectious disease physician stands as an intellectual descendent of a great lineage stretching back to Jenner, Pasteur, Koch, and Fleming and to D.A. Henderson. Those epoch-making minds were trying to solve real human problems that diminished the ability of humans to flourish. Their solutions — which include the germ theory of disease, vaccinology, and antibiotics—unequivocally augmented the length of human lifespans, diminished infant mortality, and facilitated much of modern medicine from chemotherapy to organ transplants to joint replacements.

As such, they advanced civilization. Every infectious disease physician, in their taming of even the most mundane of infections, is doing the same.

For much of human history, infectious diseases were a rate limiting check on human societies. A society might become too populous and invite crowd diseases such as measles, smallpox, and diphtheria to spread and cull the population. A society might become geographically tied to malarious areas or committed to cultural or gastronomical practices that increased interactions with specific animals, mosquitoes, and other vector species.

There have been 10,000 generations of humans and it is only the last 3-4 generations that humans have had some level of control and mastery of infectious diseases. What has transpired in that short period of time is arguably one of the most profound transformations in human history: a partial liberation from the microbial forces that shaped every preceding generation.

 In fact, it probably wasn’t actually dread as those humans were acclimatized to that baseline level of suffering, death, disruption, suboptimal lifespan, and atrocious  level of infant and childhood mortality that throttled their individual achievements and ability to reach the full potential of human life. That acclimatization still exists today in malaria endemic areas as Botswana’s President Boko recently argued).

Yet describing infectious disease as a constraint on human societies only raises a deeper question. Why does it matter that we have gained some measure of mastery over microbes? What is the purpose of that mastery? Is the goal of infectious disease

medicine simply the prevention of illness and death, or is it directed toward some higher end?

Aristotle, in the Nicomachean Ethics, argued that every craft, discipline, and human endeavor aims at some good, a telos or goal. Behind all of the intermediate or instrumental goals that people pursue lies an ultimate end: eudaimonia—human flourishing or living well.

If Aristotle is right then infectious disease medicine must also have a telos. That telos cannot simply be the eradication of pathogens any more than the purpose of architecture is the production of bricks. Pathogens are the obstacle. The end is something larger than being a pathogen hunter: preserving the conditions under which human beings and human societies can flourish.

An infectious disease physician, in my view, is a guardian of the conditions that allow civilization to flourish in the presence of pathogens. We are, to borrow the title of science writer Maryn McKenna’s excellent book on the CDC’s Epidemic Intelligence Service (EIS), “beating back the devil” in order to advance human civilization. During the COVID-19 pandemic, this role became explicit. Infectious disease physicians were called upon not merely to treat patients, but to help societies reopen schools, workplaces, hospitals, and public life itself, in effect being relied upon  to bring civilization back in the wake of the pandemic. 

There’s a scene in the movie Ghostbusters: Afterlife (I know, I try to tie this movie franchise to everything), where the teenage granddaughter of Dr. Egon Spengler, Phoebe Spengler, is asked to explain what she’s doing —  battling ghosts and investigating the paranormal—she replies simply “I am a scientist”. That scene encapsulates everything of what it is, to me, to be an infectious disease physician.

In that sense, I believe highest achievement of infectious disease medicine is not the conquest of microbes themselves, but the expansion of human freedom, civilization, and possibility through mastery of the microbial world. The late Jonathan Mann, the iconic former chief of the UNAIDS precursor agency at WHO, former state epidemiologist of New Mexico, and CDC leader once said what I evaluate as one of the greatest ways to describe the field of infectious disease. Writing about HIV/AIDS—but it applies to all infectious diseases—Dr. Mann said, “When the history of AIDS and the global response is written, our most precious contribution may well be that, at a time of plague, we did not flee, we did not hide, we did not separate ourselves.”

That, ultimately, is what infectious disease medicine is.

 

The Foreigner as Vector: America's Most Durable Public Health Myth

This week, a Kenyan court suspended a plan negotiated in secret between the Trump administration and the Kenyan government. The plan: build a 50-bed facility at Laikipia Air Base — roughly 200 kilometers north of Nairobi — to quarantine Americans exposed to Ebola in the DRC, rather than fly them home.

Kenya’s doctors’ union called the country a “dumping ground.” The Law Society of Kenya pointed out the obvious: Secretary of State Marco Rubio had just told a Cabinet meeting that the United States “cannot and will not allow any cases of Ebola to enter the United States.” If America, a first-world country, won’t accept that risk, why should Kenya?

Rubio’s line is telling. It is not an epidemiological or a medically-grounded statement. It is a political one — and it is the same political statement that has driven American infectious disease policy toward foreigners, immigrants, and “outsider” populations for decades, from both parties. It is almost always wrong. It is almost always damaging. And it never seems to go away.

The country that built 13 Ebola centers and then refused to use them

After the 2014 West Africa Ebola outbreak, the United States created something remarkable: a network of 13 specialized Ebola treatment centers with high-level biocontainment capacity. These are facilities designed specifically for this scenario — a highly lethal virus, limited natural contagiousness, spread through direct contact with blood and body fluids. They are the right tool for exactly this moment.

Instead of using them, the administration flew Dr. Peter Stafford — a 39-year-old American surgeon and medical missionary who was infected with Bundibugyo Ebola in DRC while treating patients — to Charité University Hospital in Berlin, Germany. His wife, Dr. Rebekah Stafford, and their four children were evacuated there too for monitoring. A second missionary doctor potentially exposed, Dr. Patrick LaRochelle, was quarantined at Bulovka Hospital in Prague, Czech Republic.

Two American physicians. Eight family members. Four countries. Zero American Ebola treatment centers used.

On May 18, the CDC (acting director Jay Bhattacharya signing the order) invoked Title 42 of the Public Health Service Act to bar non-citizens who had been in DRC, Uganda, or South Sudan from entering the United States. Four days later, the administration extended this authority to cover green card holders — lawful permanent residents — something the COVID-era Title 42 did not do, something none of Trump’s prior travel bans had done.

This is not a public health measure. It is the same ancient reflex, dressed in modern legal architecture.

The 1987 original sin

We have been here before.

In 1987, Senator Jesse Helms successfully added HIV to the list of “dangerous contagious diseases” that rendered foreign nationals inadmissible to the United States. The scientific logic was essentially nonexistent: HIV is not transmitted through casual contact, it does not spread through air or water, and the mode of transmission (sex, needles, blood products) is identical regardless of a person’s country of origin. HIV was, for 22 years, the only disease explicitly named by Congress in the Immigration and Nationality Act as grounds for denying someone entry to the United States.

The policy did not slow HIV transmission within the US. The epidemic spread anyway — through American communities, American hospitals, American blood banks. What the ban did do: it stigmatized an already-stigmatized population, deterred disclosure and testing, and sent the message that this disease was something that came from outside, brought in by foreign others, rather than something that spreads wherever the conditions that enable it exist.

It took until 2009 — George W. Bush signing the repeal authority and Obama’s HHS formally removing HIV from the inadmissibility list — to correct a policy that was wrong from the moment it was written. Twenty-two years of political theater, dressed as public health.

Biden punished South Africa for being honest

Administrations of both parties have played this game. In November 2021, South Africa’s scientists did exactly what the global health community asks countries to do: they identified a new, potentially significant COVID-19 variant, sequenced it rapidly, and reported it immediately to the WHO. Within days, President Biden banned travel from South Africa and seven neighboring countries.

As I said at the time: “They discovered a new variant, they sequenced it, they let the world know. Shouldn’t you be praising them? What is the incentive for the next country that identifies the next important variant if their reward is what President Biden did to South Africa?”

Omicron had already been detected in Europe, Canada, Australia, and the UK before the ban was even announced. The ban didn’t prevent Omicron from arriving in the US — it arrived almost immediately. What it did accomplish was economic punishment for scientific transparency, and the establishment of a precedent that will make every future South Africa think twice before being forthcoming.

The International Health Regulations — the internationally agreed framework for pandemic response — do not recognize travel bans as an effective public health tool. That has not stopped governments from reaching for them every single time, because they are politically useful. They look decisive. They tell voters you are doing something to keep them out.

The current Ebola response is an object lesson in what this reflex costs

The 2026 DRC Ebola outbreak is caused by the Bundibugyo species — a rare variant that standard diagnostic tests initially missed. That diagnostic delay is the main reason this outbreak, which should have been caught in the 20-to-30-case range, reached over 1,000 suspected cases before the world got a clear picture of what was happening. The delay was likely compounded by USAID dismantlement and disarray at the RFK-controlled CDC.

The travel ban does not address any of these problems. It does not improve diagnostic capacity in DRC. It does not send resources to the outbreak zone — in fact, it makes it harder to get resources and personnel in, because it chills the willingness of healthcare workers to volunteer when their ability to return home is uncertain. My colleague Alex Phelan made exactly this point in The Guardian. The cascading effect on air travel to the entire region means that even countries not named in the ban face reduced access.

Meanwhile, the US has 13 world-class Ebola treatment centers sitting empty. Dr. Stafford was sent to Germany not because Germany has better biocontainment infrastructure — it doesn’t — but because “no Ebola cases on US soil” is a political goal shorn from any grounding in medicine or epidemiology.

RFK Jr. blames immigrants. Here’s what he’s evading.

At a House Energy and Commerce Committee hearing on April 21, 2026, Health Secretary RFK Jr. — facing questions about the ongoing measles outbreaks spreading across multiple US states — said this: “It has nothing to do with me. If you’re worried about polio and tuberculosis, you should look at the immigration policies in this country. ‘Cause the place where it’s occurring are the places where the immigrants are going, because they’re not vaccinated.”

This statement requires a specific kind of rebuttal, because it is not just factually wrong — it is the inversion of what actually happened.

The current US measles outbreaks are concentrated among unvaccinated American citizens. The Texas outbreak started in a Mennonite community. South Carolina. Utah among fundamentalist Latter-day Saints. Florida. These are not immigrant communities — they are communities where American parents, influenced by the anti-vaccine movement, declined to vaccinate their children. The Mexico measles outbreak was seeded from Texas, not the other way around.

But there is a more specific and damning story here. The most striking example of vaccine hesitancy in an immigrant community in recent US history is the Minnesota Somali community — which suffered a major measles outbreak in 2017 and again in 2024. MMR vaccination rates among Somali children in Hennepin County had fallen from over 90% before 2008 to just 35.6% by 2014. That didn’t happen spontaneously. It happened because anti-vaccine groups — including Robert F. Kennedy Jr. and Andrew Wakefield — specifically targeted the Somali community with the false autism-MMR link. They held meetings in the community. They distributed materials. They exploited an existing, understandable anxiety about autism rates in the Somali-American population.

RFK Jr. and his allies created the conditions for vaccine hesitancy in a specific immigrant community. Then he stood in front of Congress and blamed immigrants for vaccine-preventable disease outbreaks.

The audacity of that position deserves to be stated directly and clearly, because it is not just hypocrisy — it is a continuation of the same tactic. Point at the outsider. Direct attention away from the actual cause. Repeat.

Title 42 for measles and TB: theater, not science

Earlier this year, the Trump administration considered reinvoking Title 42 — the pandemic-era border expulsion tool — based on claims that migrants were driving measles and tuberculosis into the United States. In March 2025, immigration law expert Agustina Vergara Cid and I analyzed this in STAT News, and the conclusion was straightforward: there is no epidemiological basis for this claim.

The bulk of US tuberculosis cases occur in legal migrants from Asian countries, diagnosed decades after arrival — not in asylum seekers from the southern border. The 2024 Chicago measles outbreak linked to Venezuelan migrants at a shelter was real — but the entire Western Hemisphere had re-achieved measles elimination status by that point, and the actual vulnerability driving US measles spread is domestic vaccination refusal, not importation from the south.

Our threshold for when an infectious disease border declaration could be legitimately contemplated is: the disease must be severely serious, must lack simple countermeasures, and must pose an epidemiologically significant importation risk. Measles has a vaccine. Tuberculosis can be diagnosed and treated to render the person non-infectious. Neither condition came close to meeting that threshold.

As we wrote in STAT: “Title 42 did nothing to blunt the impact of Covid-19 either — like the current scenario, it was a brazen attempt to use a crisis to achieve a separate policy goal.”

The CDC should not be a tool for immigration enforcement. When it is, it loses the credibility it needs to do its actual job. That is the real cost of this reflex.

What actually determines whether a disease spreads

Here is the thing about infectious disease that gets lost in every iteration of this debate: the pathogen does not check passports.

What determines whether a disease spreads in a population is not the nationality of the person who carries it into the country. It is whether the population they encounter is vulnerable to it and the transmission characteristics of the pathogen (Ebola is very constrained in that regard depending on blood and body fluid emanating from symptomatic patients). That vulnerability is a function of vaccination (when available) rates, surveillance capacity, and the ability to identify and contain cases quickly. A community with 95% MMR vaccination coverage is inhospitable to measles regardless of who crosses its border. A community where MMR rates have been driven to 35% — by a deliberate disinformation campaign — is a tinderbox waiting for a spark, regardless of whether the spark is an unvaccinated American returning from Europe or an unvaccinated immigrant from a country with low coverage.

What changes is not the science. What changes is which outbreak politicians need to deflect accountability for.

The cost we keep paying

Every time the “foreigner as vector” reflex runs its course, it costs something real.

The HIV ban didn’t stop HIV. It delayed testing, delayed treatment, and drove infected people away from the healthcare system for 22 years.

Biden’s Omicron ban didn’t stop Omicron. It established that countries which report new variants honestly will be economically punished — a precedent that makes the world less transparent about the next one.

The Title 42 Ebola ban and green-card expansion is a political tool, not an outbreak management tool. The ban does not make us safer. We have thirteen cutting-edge unrivaled centers that can handle and have handled Ebola if an American healthcare worker is infected. What the ban will do is make it harder to get responders into the outbreak zone, harder to sustain the international cooperation that containment requires, and easier for an outbreak growing at 1,000+ suspected cases to escape the region entirely.

The Kenya facility — courts permitting — would have quarantined Americans in a country with no Ebola infrastructure rather than use the infrastructure we spent a decade building, all to satisfy a political calculus that says “no Ebola shall touch US soil.”

And RFK Jr.’s immigrant-blaming, delivered under oath to Congress, will go into the record as the official government explanation for why measles is spreading in communities that his own movement depopulated of vaccine confidence.

These are not separate stories. They are expressions of the same idea: that the disease comes from them, not from us. That if we can just keep them out, we will be safe.

It is an idea with a perfect record of failure and a perfect record of political utility. That combination is why it keeps coming back.

The answer is not to restrict the movement of people. The answer is to build the population resilience — vaccination coverage, surveillance, treatment access — that makes any pathogen’s arrival an inconvenience rather than a catastrophe. We know how to do that. We have the tools to master this problem. We keep choosing not to use them, and then looking for someone to blame when the outbreak comes anyway.

The DRC Ebola Outbreak: A Predictable Diagnostic Failure

The outbreak of Bundibugyo ebolavirus in the Democratic Republic of the Congo is not, primarily, a story about a deadly and scary virus. It is a story about systemic failure — in diagnostics, in institutional capacity, and in countermeasure preparedness — that my colleagues and I have been warning about for years.

By the time you read this, the official case count is approaching 1000. The real number is higher. That gap isn’t a mystery — it’s the direct consequence of a diagnostic delay that gave the virus a several week head start. Bundibugyo is a rare species of Ebola, having caused just two prior outbreaks, and initial testing, targeted to the far more common Zaire species, missed it. By the time anyone knew what they were dealing with, untraced transmission chains were already in motion. Typical Ebola outbreaks get flagged when there are 20 or 30 cases, beginning containment when cases are in the triple digits with significant momentum is a different containment problem entirely.

This is exactly the kind of failure I testified about before the House Foreign Affairs Subcommittee in 2021. I argued then that we have a “biological dark matter” problem — undiagnosed clinical syndromes circulating everywhere, containing early signals we’re not catching because our diagnostic infrastructure isn’t looking for them. Far too many unknown infectious syndromes — from Pittsburgh to Bunia — go without a specific microbiologic diagnosis. The 20,000+ case West African Ebola epidemic of 2013–2016 offered the same lesson: Ebola had been circulating for over a decade mixed in with (and likely mistaken for) Lassa Fever cases. Guinea took three months to realize it was dealing with an Ebola outbreak and not cholera. The trajectory of the current DRC outbreak echoes the past.

What made this outbreak worse is that the US surveillance infrastructure that would have sounded the alarm earlier has been dismantled. USAID, which operated in the DRC, was impacted by DOGE program. In addition, the director-less and RFK Jr-beholden CDC has lost over 700 people from its emerging-disease activities — employees and contractors — including the head of the high-consequence infectious disease group directly responsible for Ebola response. The storied agency that was once first on the ground, first to brief the world, now can’t even participate directly with the WHO without asking permission.

A major aspect of the US response to all this has been a travel ban — on DRC, Uganda, and South Sudan. It is the wrong move, for the same reasons it has always been the wrong move. Travel bans, though a favorite tool of politicians who want to appear as if doing something, impede the flow of personnel and resources intooutbreak zones. Healthcare workers who might volunteer to fight this outbreak will now have to contemplate being corralled by the policy. Other countries follow suit with cascading bans. As such, the International Health Regulations oppose travel bans. They are not evidence-based and objectively harmful. Targeted travel screening is what works. Blanket restrictions have the very real potential to postpone the extinguishing of outbreaks at their source. Critically, the US has 13 NETEC biocontainment treatment centers built precisely for this, and we should be vigilant and proactive without being rattled.

There is also a countermeasure reality to face: there are no approved vaccines or specific treatments for Bundibugyo ebolavirus. The drugs that worked so well in the DRC’s 2018–2020 outbreak are specific to Zaire ebolavirus. They don’t reliably cross-protect against Bundibugyo. BARDA is advancing a monoclonal antibody that targets Ebola Sudan and may have some cross-reactivity (it is likely the treatment that Dr. Stafford has received in Germany), and Oxford and the Serum Institute of India are working on a vaccine using the AstraZeneca COVID platform that might be field-deployable within months.

This countermeasure gap extends to other filoviruses as well. Neither Ebola Sudan nor Marburg, both of which have causes recent outbreaks, have countermeasures as well. These are filoviruses with case fatality rates that routinely exceed 50 percent, and we have had no licensed tools against them. We built countermeasures for Zaire ebolavirus in response to its potential use as a bioweapon and the magnitude of the outbreak 2014. We have not applied the same urgency to the rest of the family, and every outbreak of Sudan virus or Marburg is a reminder of why a viral family approach is desperately needed.

The post-COVID media continually wants to know if this outbreak is “the next COVID” (as they did for hantavirus). The answer is no — Ebola spreads through blood and body fluids, not the respiratory route. Its transmission is constrained. Ebola is a virus that spreads through direct contact with the bodily fluids of the sick and the dead — it finds exactly what it needs in overwhelmed clinics with no PPE and burial traditions that involve touching the body, but the moment it lands somewhere with isolation rooms and infection control, it is quickly stopped in its tracks. They also mention The World Cup. Mass gathering events are perfect venues for crowd diseases such as those caused by a respiratory or gastrointestinal virus — measles, influenza, COVID, norovirus — diseases that spread through the air and via causal contact requiring little more than proximity. Ebola requires you to be in direct contact with someone who is visibly, severely ill and is not a crowd disease.

The real worry isn’t what Bundibugyo will do to the American public. It’s what our hollowed-out response infrastructure will do when the US inevitably faces a true pandemic threat.

Germ Theory is Not a Narrative

Multiple times in recent weeks, people have posted some version of the same claim on my social media accounts: viruses don't exist. The comments usually arrive with a set of caveats — cell culture techniques don't count as evidence, electron microscopy is interpreted too liberally, the photographs are artifacts. This is a total absurdity.

The evidence for the existence of viruses is incontrovertible and manifold. In 1892, a Russian botanist named Dmitri Ivanovsky passed the sap from diseased tobacco plants through a Chamberland filter — a porcelain filter fine enough to trap every known bacterium — and the filtrate still caused disease. Something was passing through that no bacterium could. That was the first documented encounter with what we now call a virus. Over the following century, the evidence compounded and converged: electron microscopy visualized viral particles directly beginning in the 1930s; fluorescence microscopy tracked their movement through living cells in real time; cytopathic effect — the characteristic pattern of cell destruction that differs systematically by pathogen — became a diagnostic standard that clinicians use today. These are not interpretations. They are observations, replicated independently on every continent, across 130 years.

The reason scientific evidence is inadmissible in these discussions is not because it is weak. It is because the people making these arguments have pre-rejected the epistemological framework which includes the scientific method. In their wicked egalitarianism, no one's standpoint is closer to reality than anyone else's — a virologist peering through an electron microscope has no more claim to truth than the person who watched a YouTube video about it. To even call this an argument gives it too much respect. It is the complete flattening and destruction of the concept of expertise.

That philosophical infrastructure underlies what is now US health policy. RFK Jr., the current Secretary of Health and Human Services, overtly questions germ theory in favor of what he calls terrain theory — the claim that what we label infectious disease results not from external pathogens but from an unhealthy internal "terrain." This is not a new idea. It is miasma theory, the discredited framework that predates Pasteur's epoch-making development of germ theory. Sanitation does matter — it reduced infant mortality meaningfully, and no one disputes that. But sanitation explains declining death rates from cholera and typhoid. It does not explain the elimination of smallpox, the near-eradication of polio, why pediatric wards are no longer filled with children with Hib meningitis, the survival of children who would otherwise have died of Hib meningitis. Vaccines and antibiotics explain those. The terrain model cannot account for what Fleming found growing on that contaminated petri dish, or what Jenner observed when the milkmaid who'd had cowpox didn't contract smallpox.

For many adherents of this worldview, infectious disease expertise (even when discussing a non-communicable disease) is inseparable from social control. Public health becomes not a response to pathogens but a mechanism of coercion. In this framing, outbreaks justify restrictions, experts become instruments of (bio)power, and skepticism itself becomes a form of resistance. The field of infectious disease medicine has been recast as a psyop designed to implement an agenda of social control. They respond with what the philosopher Foucault called counter-conduct: not just rejecting medical authority but appropriating its language — informed consent, bodily autonomy, "do your own research" — while treating ivermectin as a tribal symbol and any pathogen as a pretext for political theater.

I wonder whether they would have discouraged Jenner, Pasteur, Koch, and Fleming from trying to solve the human problems that infectious diseases posed. These were not agents of control. They were scientists who looked at people dying of preventable diseases and refused to accept it as the natural order of things.

D.A. Henderson's smallpox eradication campaign was not an act of biopower. It was an act of human reason applied to a significant and deadly human problem. That is what infectious disease medicine is — and has always been. Germ theory is not a narrative. It is a description of reality. As an infectious disease physician, I have treated patients with illnesses whose course changed because germ theory was true: bacterial infections halted by antibiotics, opportunistic infections prevented with antimicrobials, diseases made rare by vaccines. My field has always fought for civilization by trying to master an inhospitable natural world (as it always has) — it now faces an anti-human attack wielded by an army of postmodern nihilists who have been granted government power.

Vaccination is Liberation

Every summer for most of human history, parents watched their children with dread. Not because summer was dangerous in the way we mean today — it was something more specific and more terrible. Pools were closed. Crowded places were avoided. A child who woke up with a fever and leg pain was a child who might never walk again. Polio was seasonal. Parents knew this. They planned around it. They feared it the way you fear something that doesn't announce itself before it takes.

That was the normal condition of human life before vaccines. Not the exception. The norm.

In the 20th century alone, smallpox killed an estimated 300 million people — more than all the wars of that century combined. Before Edward Jenner developed the smallpox vaccine in 1796, the disease killed roughly one in three of those it infected and blinded many of those it didn't. In 18th century Russia, every seventh child born died from smallpox. It was not an anomaly to dread. It was a tax that nature collected on the act of being born.

We ended it. With a vaccine. In 1980, the WHO certified smallpox eradicated — the only human disease ever fully extinguished. That is one of the most extraordinary achievements in the history of our species and was led by DA Henderson, a mentor to me and larger than life Homeric hero.

What vaccines actually are

We haven't properly understood what vaccines are. They are liberation technology. They are what happens when human beings refuse to accept nature's terms.

Energy expert Alex Epstein has a concept he calls "climate mastery." His core argument is that the right question about climate isn't how to minimize our footprint — it's how to build the technological capacity to master climate dangers. Humans don't just "adapt" to storms, drought, and extreme temperatures; we build levees, irrigation systems, and weather-forecasting networks. The result: climate-related deaths have fallen roughly 98% over the last century, even as the human population more than tripled.

The same principle, applied to the microbial world, is what I'd call infection mastery. Nature has never been on our side. Viruses and bacteria do not intend harm — they have no intentions at all. They replicate, mutate, and spread because that is what selection pressure optimized them to do. Infectious disease has always been the price of living on a planet that was microbial long before it was human. For most of history, that price was paid in full — with paralyzed limbs, blind eyes, dead children, and shortened lives. There have been 10,000 generations of humans and it’s only the last 4 that humans have been able to master some infectious diseases.

Vaccines are infection mastery in concentrated form. They don't ask us to accept the disease burden nature imposes. They allow us to build immunity without paying the cost of the disease itself — to take the lesson without the punishment. The result: polio, which paralyzed tens of thousands of American children per year in the 1950s, has been eliminated from the Western hemisphere. Measles, which killed 2.6 million people per year before the vaccine, is now eminently preventable — when we bother to use it. The HPV vaccine prevents cervical cancer. The flu vaccine reduces heart attacks. The shingles vaccine cuts stroke risk. These tools don't just stop infections; they reshape the entire downstream arc of a life.

The misunderstanding that keeps getting people killed

Some people frame vaccination as humans "interfering" with nature, as if nature had a preference worth respecting. But this gets the relationship exactly backward. The human immune system, the human brain, the capacity for abstract reasoning that lets a scientist synthesize an mRNA vaccine in a year — all of that is nature. It evolved. When we make a vaccine, we aren't defying natural selection. We are what natural selection produced: a species capable of turning reason outward onto a hostile world and making it less lethal. On my first trip to the Galápagos, where Darwin amassed the observational data needed to formulate the theory of evolution via natural selection, a naturalist guide told me humans shouldn't interfere with how infectious disease shapes our species. My answer then is what it is now: building tools to master infection is the most natural thing we do. It is natural selection completing itself through us.

This is why the current erosion of vaccine confidence isn't just a public health problem. It is a civilizational one. Measles is spreading across American states not because we lack the tools to stop it, but because we have chosen to walk away from them — to voluntarily return to a world our grandparents spent their lives escaping. The West Texas outbreak, the Florida cases, exposures at Lincoln Center, and South Carolina— these aren't bad luck. They are the predictable result of surrendering infection mastery to ideology.

If a 98% reduction in climate deaths counts as mastery, what do we call the eradication of smallpox? What do we call a world where your child doesn't spend August in fear of a limp? We call it what it is: a triumph of human reason over nature's indifference. And it is ours to lose.