We don’t know their names. We almost certainly never will. But beginning on February 11, 2022 108 healthy adults from across the United States performed an act of selfless generosity. Twelve went first. They were the guinea pigs, those willing to ensure the safety of others by taking the risk of whatever might go wrong.
Nothing did, so three times over the course of twelve weeks the group bared their arms and allowed strangers to poke them with a needle, through which flowed something new, a substance never before inserted into human bodies. A handful of them reacted to those injections—most often experiencing a bout of hives—but, on the whole, the study subjects handled the experimental compound well.
These were ordinary people. As near as possible, they were a cross section of the US population. Some were as young as eighteen, some were sufficiently ancient to have made it to fifty-five. Just over half were men; one in six were Hispanic or Latino. They put up with a lot from the team of researchers: multiple blood draws, the last coming nine months into the study. Finally, in 2025, the work was done, and on July 30, the research team published its results.
The study had tested three different formulations of its new shot. One didn’t work, but the other two did: for 80 percent of the study subjects they induced significant immune responses. This was a preliminary, phase one clinical trial, so there was still a long way to go to confirm that this approach really could achieve what its inventors hoped—stopping an invader dead in its tracks.
So far, this reads like just another incremental advance in the usual process of medical research. But the target was the human immunodeficiency virus, or HIV—the pathogen that causes AIDS, which, left untreated, kills virtually everyone it strikes; that has already taken over 40 million lives; and that still finds more than a million new victims each year.
Now, especially in the richer half of the world, we are (mostly) free from that scourge. But that freedom has always been fragile, utterly dependent on access to and willingness to use the instrument of our liberation: vaccines.
That’s the gift the hundred or so regular folks who volunteered for the study have given the world: they’ve advanced the prospect that humankind may free itself from the threat of HIV/AIDS, a half a century after the disease first appeared. If—when—this comes to pass, it will be because these people, and countless others to come, will have helped invent, test, refine, and finally deliver the ultimate defense against infectious disease: a vaccine.
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Vaccines are a secular miracle, or, as futurist and author Arthur C. Clarke might have said, “are indistinguishable from magic.” Something invisible dissolved in a syringe confronts something invisible inside someone—and an event doesn’t happen. That person won’t suffer measles or polio or typhoid, or a host of other conditions. Magic!
Or better, not the work of sorcery but an unmatched triumph of human inquiry and technical skill—over death itself. Consider what life was like before humankind learned to induce immunity to infectious diseases: often nasty, sometimes brutal, and definitely short. In 1800, just as the first true vaccine—against smallpox—came into use, life expectancy at birth hovered around thirty years worldwide. Infectious disease was the leading cause of death, as it had been for centuries. Before its vaccine became available, smallpox by itself accounted for eight out of every hundred deaths in some of the wealthiest and healthiest nations, and more where conditions were worse.
As the decades passed, the crowding and filth in the rapidly growing cities in the industrializing nations of Europe and North America created perfect conditions to fuel epidemic outbreaks that could steal the lives of those of any age or rank, but were most dangerous for the very young. In those years, the concept of specifically “childhood diseases’—diphtheria, pertussis (whooping cough), measles and some others—took shape.
By 1900 that landscape of disease was beginning to change—but slowly. Richer parts of the world were doing better: the US and England saw life expectancy at birth rise to about forty-seven or a little more. Then everything changed. By the middle of the century, the global population could expect to live on average about fifty years. Seven decades later that number has climbed to seventy-three, while those in the richest nations have surpassed an average of over fourscore years, a number the Bible reserves for only the most vigorous among us.
Thank vaccination. It wasn’t the only driver of this radical shift in human possibility, but as the modern suite of vaccines emerged, rendering harmless (or at a minimum, much less harmful) each malady in sequence, they caged one prolific killer after another. Perhaps most important, they have saved our babies. For much of history, before humans learned how to engineer immunity, almost every parent had to bury at least one of their children, and often more. In the middle of the eighteenth century, a few decades before the first true vaccine (against smallpox) emerged, as many as seventy-five out of every hundred infants baptized in any given year would perish before they reached their fifth birthday.
The full suite of vaccines against childhood diseases was almost complete by 1970. In that year in the United States the number of lost kids had dropped to just over two per hundred. By 2020, it became necessary to move the decimal point on that calculation. Only four out of every thousand babies born would not make it to five. For humanity as a whole, the World Health Organization has calculated that over the last fifty years alone vaccines have preserved 154 million lives—that’s 10:2 billion years of healthy life gained. Almost all of those lives reclaimed were children. It is no longer routine, just part of the business of living, to outlive one’s own child.
To paraphrase what is said every year at the Jewish holiday of Passover: all of us once were slaves—not to Pharaoh, but to infectious disease. Now, especially in the richer half of the world, we are (mostly) free from that scourge. But that freedom has always been fragile, utterly dependent on access to and willingness to use the instrument of our liberation: vaccines, those already here and the ones yet to be invented. As I write this in the summer of 2025, vaccination is under existential threat in the United States—and increasingly so throughout the world.
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The face of the immediate crisis is Robert F. Kennedy Jr., who in 2021 was found by a group of independent researchers to be one of the top sources of misinformation on COVID vaccines and treatments. Four years later Donald Trump appointed and fifty-two Republican senators confirmed him as Secretary of Health and Human Services. In his first few months in that office Kennedy steamrolled every facet of American vaccine infrastructure. Weeks into his tenure, he fired the entire outside panel of experts who guide CDC vaccine policy, replacing them with a group that included anti-vaccination activists and contained no one with expertise in the relevant fields. At the same time, he revived false claims about a connection between vaccination and autism. Then, he moved swiftly to restrict approval of COVID vaccines to those over sixty-five or who suffer other conditions that increase their risk. A week after that move, he withdrew recommendations (effectively, approval) for their use for pregnant women and otherwise healthy kids.
There’s more: he closed agencies that prepare for novel pandemics; appointed “skeptics” to key vaccine regulatory positions; hired someone who had previously been disciplined for practicing medicine without a license to run a new vaccine-autism “study,” while promising to identify the causes of that condition within six months. All this while presiding over the largest outbreak of measles in the US in more than two decades, which by June 2025 had killed three people in a wholly vaccine-preventable tragedy. Labelling vaccines a “personal choice,” he lied about the rate of side effects from the measles vaccine, while suggesting that those who do fall ill can be successfully treated with cod liver oil, antibiotics, and steroids. (They can’t.)
With each passing month, his assault has deepened. In early August, after welching on a half-billion-dollar commitment in May that would have paid for a vaccine against bird flu—a relative of the virus behind the devastating 1918 pandemic—Kennedy cancelled grants and contracts worth another $500 million that were intended to develop a range of vaccines using mRNA technology. That biochemical tool made it possible to create COVID vaccines within less than a year. As former Trump health official Rick Bright told The New York Times, killing off US mRNA research undermines “our ability to rapidly counter future biological threats,” a decision, according to Chris Meekins, another first-term Trump public-health appointee, that amounts to a “national security vulnerability.”
Even that isn’t the greatest danger on the way. In August 2025, Kennedy announced his intent to alter the Vaccine Injury Compensation Program, which pays out to those who have suffered—or believe they have—some harm caused by a vaccine. The system was set up to streamline the process of getting compensation while shielding vaccine manufacturers from unlimited liability for any issue with their products.
There are several real problems with the compensation program; it’s underfunded and so drastically understaffed that claims can take years to resolve. But rather than addressing them, Kennedy appears to be attempting to push vaccine compensation on to the civil court system—and, potentially, expose drug makers to unlimited liability. A jury could conclude a vaccine injury occurred (even if no causal connection had been established) and there would be no cap on what a manufacturer might have to pay. That was the situation in the 1970s and 1980s. By 1986, this legal jeopardy drove all but one vaccine manufacturer out of the market, with that last survivor poised to abandon vaccines in the US as well. This was when the current compensation scheme went into effect. If Kennedy succeeds in killing that system, the same business calculation will apply. Many, perhaps most, existing vaccines could be forced out of the market in the United States, and everywhere else the vaccine panic takes hold, while the development of new shots would become almost impossible. Should this come to pass, Kennedy and his allies will have succeeded in Making Microbes Great Again—to our swift and deepening sorrow.
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Kennedy and his allies within the Republican Party and the wider movement behind them have consistently made three arguments as to why all of us should abandon vaccination. First: vaccines are unnecessary, a disruption of nature and the healing powers that a healthy mind and body possess. Second: vaccines are not merely surplus to requirements for anyone who lives the right way, they’re actively harmful, worse than any hazard of the diseases they (allegedly) prevent. And third: that whether vaccines are effective or not, it is intolerable for the state to make them compulsory under any circumstances; that what has been termed “medical liberty” trumps any greater good that near-universal vaccination could possibly achieve.
The first two claims are false. Certainly, there’s no doubt that your environment makes a difference to your wellbeing. Clean air and water, adequate nutrition, emotional calm and the rest of the “wellness” suite of remedies are fine in themselves and can indeed help reduce the peril of a given illness. But no amount of healthy living will keep a child from catching measles if, unprotected, they encounter that incredibly infectious virus. Polio doesn’t care if your diet is organic and vegan. Smallpox, for millennia among the most feared infectious killers, was rendered extinct in the wild in 1979. It was eliminated not because water supplies are cleaner now than they were in the nineteenth century, but because its vaccine, the first more-or-less modern one in the medical arsenal, proved effective. Vaccination works, and what it does—teaching immune systems how to recognize and counter pathogens—cannot be accomplished simply by taking good care of yourself or your kids, no matter how beautiful a lifestyle you manage to maintain.
Similarly, vaccines are safe. Not perfectly so—nothing in life is a completely sure bet, and human error can and has led to a handful of genuine tragedies. But vaccine complications are rare, mostly mild, and orders of magnitude less dangerous than encounters with the diseases they prevent or ameliorate. For one example among many: there are serious but rare adverse events associated with COVID-19 vaccines. But even those bad outcomes have not led to any increase in the ultimate risk—death—for the vaccinated compared to the unvaccinated. Stories like the original paper that asserted a link between the measles vaccine and autism or Kennedy’s statement that the COVID vaccine is “the deadliest vaccine ever made” are not true. They are false.
The third strand of anti-vaccine advocacy, that compelling vaccine use is unacceptable, is a philosophical claim, not one of fact. There’s a vision of society in such a view. It is one in which its members live autonomous lives, pursuing their own goals with no consideration of the consequences for any other person. It’s the human equivalent of an ideal gas, an atomized existence in which each molecule follows its own trajectory, independent of all others. There is an alternative to such a view, one which recognizes that there are bonds that connect people within a society. Those ties impose a limit on what we can do—if our choice of action has an impact on someone else.
As an abstract argument there is no necessary winner or loser between those two poles of belief. But microbial pathogens don’t participate in human philosophical disputation—and once they lodge inside the body of someone who chooses not to vaccinate they can and do spread where they will. In the last extreme, that means that one person’s exercise of their free will deprives someone else of all their rights. There is no liberty in the grave.
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All this is to say that when tested against the facts, each pillar of the current indictment of vaccination fails. So why have these objections remained so potent? In part, that’s because for much of the history of the three main themes of the anti-vaccine case, there was always at least some truth, something plausible, in these long-standing objections to vaccination.
For example, the prescription offered by those who saw a generally healthy way of life as the right way to prevent disease helped propel cleaning up the filthy cities of the Industrial Revolution—and that really did reduce the impact of common fevers. Early vaccination techniques, not yet perfected, did lead to genuine harm, in some cases causing the very infections they were intended to prevent. The first attempts to compel vaccination in the 1850s appeared to many to be arbitrary and unneeded extensions of state power at a time when the effectiveness of the shots was still very much in dispute. Simple human error always posed some risk, but as science advanced those small risks were ever more mitigated. Vaccines did and do what they are supposed to: provide vast benefits with a real but tiny residue of complications; and they defend society as a whole from the misery that comes in the wake of unchecked infectious disease. But their history is more complicated than a simple tale of ever-greater triumph.
Microbial pathogens don’t participate in human philosophical disputation—and once they lodge inside the body of someone who chooses not to vaccinate they can and do spread where they will.
That’s the first half of what this useful past reveals. Yes: there were open questions that needed to be addressed to transform early experiments in vaccination into standard medical practice. But while objections to the idea of engineering immunity to disease have remained essentially the same over the last two centuries, their meaning has changed, transforming what was once arguable into the lies that drive our current peril. As each flaw and error in the early development of vaccines became clear, researchers and practitioners responded, fixing problems as they were identified. At the same time, the science underlying vaccination has changed beyond recognition, driven by the singular breakthrough discovery in the late nineteenth century that microbes—bacteria and virus—cause infectious disease. This provided the key insight on how vaccines work, which in turn led to the twentieth-century conquest of the most common infectious diseases. Thanks to more than 200 years of intense and virtuoso scientific work, what were once valid or at least plausible concerns and objections to vaccines have been overcome.
Alas, as the current crisis confirms, such mere facts do not persuade those leading the anti-vaccine crusade that threatens both existing protections and the hope of creating new ones. When today’s anti-vaccine proponents repeat their familiar claims, they’re reanimating zombies, long-argued and ultimately debunked claims about vaccines—and they’re flooding the information ecosystem when they do.
Here are the gleanings of just a single week in September 2025. First, Florida Surgeon General Joseph Ladapo announced the end of vaccination requirements in his state, emphasizing the tyranny of basic public health. Vaccine mandates drip “with disdain and slavery,” he proclaimed, and no government should “tell you what you should put in your body.” The next day, Lance D. Johnson reassured his readers that there was no need to worry about the consequences of that decision because “The human immune system is a marvel of divine engineering,” offering a better way than any vaccine to fight off disease. “It adapts, remembers, and overcomes pathogens,” Johnson, a Florida-based anti-vaccine activist wrote, “with a precision no syringe can match.” That would come as a surprise to variola major, the virus that caused smallpox, driven to extinction by a vaccine.
Finally, to cap that single week’s tally of potentially lethal misinformation, British cardiologist Aseem Malhotra told the UK right-wing Reform Party’s annual conference that vaccination was not merely wrong, it was outright dangerous, proclaiming that “it’s highly likely that the COVID vaccines have been a significant factor in the cancer of members of the royal family.”
Yet more arrant nonsense, coming from someone who has repeatedly been cited for spreading vaccine misinformation. But as the old saw has it, a lie goes round the world while the truth is tying its bootlaces. Such undead falsehoods drive our current peril. Not knowing their history, we risk repeating it.
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Vaccination is one of the greatest gifts humanity has ever given itself. Recall those hundred or so volunteers who put their own bodies on the line to advance the possibility—absolutely not the certainty—of eliminating a brutal scourge, HIV/AIDS. None of them will likely benefit from the hazards they accepted by joining that trial. Their phase of the experiment centered on establishing the safety of the vaccine, not its value. And yet they rolled up their sleeves and accepted the needle.
There’s a vision of a possible future in such generosity. The surrender to infectious disease that some of the worst among us contemplate is not inevitable. We don’t have to acquiesce to what Kennedy and his allies have set in motion. The job for the rest of us is to defend that vision—and advance it.
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From A Pox on Fools: The True Believers, Grifters, and Cynics Who Convinced Us to Reject Vaccines by Thomas Levenson. Copyright © 2026. Available from Random House, a division of Penguin Random House, LLC.
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