Meta also agreed to make changes to its platforms, including implementing a two-hour cumulative, daily time limit across its apps for users aged 13 to 17 that only parents can change; prompting teens after every 15 minutes of continuous use of Facebook or Instagram to encourage intentional use; and implementing a default night mode, blocking access to the apps from midnight to 6 am for teens, and a school mode, designed to reduce the number of notifications teens receive during school hours. Meta will also hide the number of likes and reactions on teens’ posts by default and will give teens the option to turn off autoplay and choose a feed not based on algorithmic recommendations as their default.

The Meta settlement represented prevention arriving late. The warning signs about addictive design and harm to children had accumulated for years, but meaningful guardrails came only after widespread injury, public pressure, litigation, and enormous cost.

That evening, Microsoft co-founder Bill Gates appeared on CNN’s Anderson Cooper 360. Gates argued that artificial intelligence needs significant limits or else the harm to humans will outweigh any potential good. He noted that AI models have gotten dramatically more powerful at a rate faster than he expected. Gates advised leaders to 1) act immediately before unemployment soars, communities suffer, and public trust wanes and 2) make sure AI helps everyone and collaborate with other countries to solve this global problem.

Bill Gates’s warning about AI represented the other possibility: recognizing a consequential danger while society may still have time to shape the technology, establish safeguards, and prevent foreseeable harm.

Guardrails for Social Media and for Artificial Intelligence
The former needs fixing and the latter is under construction.

Together, these stories captured a pattern I have written about repeatedly. With social media, warnings emerged, evidence accumulated, action was delayed, and harm continued until litigation finally brought accountability. With AI, the warnings have arrived while uncertainty remains. This time, however, we may still have an opportunity to act before the damage becomes widespread.

The contrast presents us with a choice. We can continue to impose guardrails only after harm has become undeniable, or we can build them while the risks are still emerging. Social media shows the cost of treating prevention as an afterthought. AI gives us another chance, perhaps a rapidly narrowing one, to make prevention part of the technology’s design from the beginning.

Prevention does not require predicting every consequence or stopping innovation. It requires taking credible warnings seriously, looking carefully for evidence of harm, assigning responsibility, and acting before the damage itself becomes the evidence that finally compels us. On August 26, one technology showed us what happens when we wait. The other asked whether we will wait again.

Clayton County was not alone. Beginning that same day, the FBI and EPA counted cyber incidents at water and wastewater utilities in at least seven states. The attacks targeted internet-connected controllers, and several degraded operations. We tend to file such events under technology, but they are also part of public health. When pumps fail, or treatment slips, or monitoring goes dark, the harm shows up in kitchens and clinics rather than in server rooms.

That brings us to Benjamin Franklin. This month, DEF CON Franklin and the National Rural Water Association opened the Water Watch Center. It sends volunteer security experts to small utilities that will never staff a cyber team of their own. The name honors Philadelphia’s Union Fire Company, which Franklin organized so that neighbors could protect one another and their community from fire.

Franklin also gave us the line that names this newsletter. He wrote it in 1735 about fire rather than medicine: an ounce of prevention is worth a pound of cure. Three centuries later, the hazard hides in an exposed controller instead of a chimney, and the advice still holds. Find the weakness before catastrophe strikes.

Six days later the story repeated north of the border. The Bald Range fire started on a Friday evening west of Okanagan Lake, ran roughly nine miles toward the water within hours, and drove more than 20,000 residents out of Summerland and Peachland. British Columbia declared a provincial emergency. An eighty-year-old woman from Meadow Valley died while trying to leave her home with a family member. The blaze grew hot enough to build its own thunderstorm and throw its own lightning.

Bald Range Fire

These are not bigger versions of the wildfires we grew up with. John Vaillant named the category in Fire Weather: On the Front Lines of a Burning World, his 2023 reconstruction of what happened to Fort McMurray, Alberta, in May 2016. That town was no remote outpost but a prosperous center of Canada’s oil industry, and the blaze still drove 88,000 people from their homes in a single afternoon and turned whole neighborhoods into fuel. A city built on extracting fossil fuels nearly burned to the ground in the hotter, drier world those fuels helped create.

Vaillant could have filed all of that as a report. He chose instead to tell it through residents, firefighters, and officials, so the reader feels the speed and the heat and the confusion rather than counting structures lost. Rachel Carson did the same thing with pesticides in The Silent Spring, and Randy Shilts did it with the first years of AIDS in And The Band Played On, each taking evidence the specialists already held and giving it a shape the public could carry. Fiction lets us imagine a possible future and then set the book down. Nonfiction removes that exit.

On July 27, Vaillant told Democracy Now that blazes in France and Spain were throwing flames past a hundred meters, the height of a thirty-story building, and that French pilots watched thousands of gallons evaporate in the radiant heat before the water reached the fire. He called what we have built a “chimera of fire.” His prescription is emissions, full stop. Cut them, he says, because lowering the temperature is the only way to lower the fire risk.

He is right, and he is describing only half of the work. Twenty-three summers ago the same valley burned. The Okanagan Mountain Park fire destroyed 239 homes and pushed 27,000 people out of Kelowna, and British Columbia asked former Manitoba premier Gary Filmon to find out what had gone wrong. His review returned 42 recommendations, 18 of them on prevention and mitigation, centered on thinning the fuel around communities and putting low-intensity fire back on the land before the high-intensity kind arrived on its own. Two decades later the province had treated about 16,000 hectares, roughly two percent of the ground it had flagged as high hazard. Bald Range burned more land in three days than British Columbia treated in twenty years.

Prevention fails at four points: recognition, evidence, translation, and implementation. Here it failed at the last one twice. We are not cutting greenhouse gas emissions, so the heat and the drought that make these fires keep building. We are not thinning the fuel, hardening the roofs, or carrying out any serious share of those eighteen recommendations, so the damage keeps landing on whatever stands in the way. Either course would have helped. We are doing neither, and the damage from the wildfires continues.

A novelist was paying attention. Paolo Bacigalupi looked at Texas and saw something other than a bad year. In 2015, he published The Water Knife, a novel about a shrinking Colorado River, states at war over what remained, and cities where heat and scarcity sorted people into those who could pay and those who could not. Reviewers called it dystopian fiction. In a 2025 interview marking the book’s tenth anniversary, he rejected the label. He had taken climate projections, drought records, and the existing fight over the river, and carried them forward.

Two weeks ago, the extrapolation collided with the headlines. On July 31, the Bureau of Reclamation released its Final Environmental Impact Statement for operating Lake Powell and Lake Mead after the current rules expire in December. The preferred alternative would cut the combined use of Arizona, California, and Nevada by as much as 130 billion cubic feet a year through 2036. Seven states have spent three years failing to reach a deal, and a federal agency has stepped into the vacuum they left.

None of this arrived without warning. Reclamation’s own basin study laid out the supply and demand imbalance in 2012, and researchers have documented the thinning snowpack and an almost twenty percent decline in flow since 2000.

Bacigalupi does offer one revision after ten years. He judged the environmental danger about right, he says, and badly underestimated the political dysfunction surrounding it. That is the more unsettling half of his answer. I have argued that prevention breaks down at four points: recognition, evidence, translation, and implementation. The Colorado River cleared the first three decades ago. What remains is the fourth gap, and it overwhelms everything.

Past novels have awakened and aroused the public over important issues. The Jungle put readers inside a Chicago packinghouse and helped drive the food safety laws of 1906. The Grapes of Wrath made the dispossession of farm families impossible for a comfortable nation to ignore. Neither book discovered anything new. Both took conditions that inspectors, economists, and reporters had already described, and turned them into people whom readers could not set down and forget.

In the climate chapter of The Preventioneers, I argued that we need more novels, films, and plays about the world our current choices are building. Science can tell us that a river is disappearing. A story can tell us what its loss would mean. Spicewood Beach already knows.

French wildfires 2026

Last week, something happened in France that had never before been officially recorded. A wildfire in the southwest region of the country became so powerful that it generated a thunderstorm. This was not the world’s, or even Europe’s, first pyrocumulonimbus, or fire-generated thunderstorm cloud. Similar events have been documented in Portugal, Australia, Canada, Russia, and the United States. But the storm produced during France’s wildfires showed that this phenomenon is spreading. It is a warning that the relationship between wildfire and the atmosphere is changing.

How pyrocumulonimbus clouds are formed

A pyrocumulonimbus forms when heat, smoke, and moisture rise rapidly from an intense fire. As the plume climbs and cools, water vapor condenses around particles of ash and may develop into a thunderstorm, producing lightning, sudden shifts in wind, and showers of burning embers that ignite new fires.

On January 18, 2003, a wildfire near Canberra, Australia, grew so intense that it produced a towering pyrocumulonimbus cloud. Violent winds, lightning, and even a documented fire-generated tornado. See the video. Four people died, hundreds of homes were destroyed, and the fire essentially began controlling the weather rather than being controlled by it.

Scientists have studied these storms for years, and their warnings have been specific. The most powerful of these storms can lift smoke high into the atmosphere, sometimes as far as the stratosphere, where it can linger for months. Researchers have found that this smoke can affect atmospheric chemistry and ozone and can temporarily alter temperatures and atmospheric circulation.

A global inventory identified 761 confirmed pyrocumulonimbus events between 2013 and 2023. Within that eleven-year record, 2023 had the highest total, with 169 events worldwide, including 142 in Canada. Changes in satellite detection and reporting can affect the number identified, so the inventory alone does not prove a continuous worldwide increase. It does show that these storms occur across a wider range of regions than many people realize.

Climate change is increasing many of the conditions that allow extreme fires to develop. In many regions, the weather conditions that favor severe fires are becoming more common or more intense. In southeastern Australia, researchers project more days suitable for pyrocumulonimbus formation, especially in spring. Hotter and drier fuels increase the potential for intense fires, while atmospheric instability can allow their smoke plumes to grow into thunderstorms.

One of the recurring lessons of history is that disasters often evolve faster than our willingness to prepare for them. Scientists have spent decades warning that hotter, drier conditions would make extreme wildfires more likely. Pyrocumulonimbus reminds us that prevention is no longer only about reducing greenhouse gas emissions. It is also about adapting to a world where fires can become so intense that they create their own weather.

Cutting greenhouse gas emissions remains essential. At the same time, communities must prepare for the dangerous fire conditions they are already facing. Wildfire mitigation may feature carefully managed prescribed burning, grazing, vegetation removal, and better management of forests and abandoned land. Wildfire adaptation might incorporate ember-resistant buildings, earlier warnings, safer evacuation planning, and specific emergency plans for care homes, hospitals, and isolated communities.

France’s first recorded pyrocumulonimbus shows that European fires can reach levels that make suppression far more dangerous and uncertain. The test now is whether governments can reduce fuels, strengthen communities, and improve warning systems before these conditions become more common.

Addendum: I finished this piece over the weekend. The wildfires are now in the United States, in Washington state. These phenomena are due to extreme summer heatwaves and severe drought conditions. While they are separate geographical events, they are part of the global climate crisis.

A Prevention Champion Is Trying to Make Us Notice

Stand on the rim above Lake Mead and you can read the crisis on the canyon walls. A chalk-white mineral ring marks where the water used to be, and on July 12, 2026, the reservoir stood more than 175 feet below its normal full level. On that date, Lake Mead slipped below 1,043 feet, and upstream on the Colorado River, Lake Powell stood at 3,524 feet. Together, the two reservoirs held less water than at any point since 1957, six years before Lake Powell began filling, back when the modern Southwest had not yet staked its future on this river.

The white “bathtub ring” along Lake Mead’s canyon walls consists of mineral deposits left by higher water levels.

Five Colorado River experts published the analysis behind those numbers, among them Jack Schmidt, director of the Center for Colorado River Studies at Utah State University. Schmidt called the new low “a milestone in the history of water storage in the Colorado River Basin.” When a career river researcher uses the word milestone, he is telling us something. Schmidt deserves attention not only as a scientist but as a prevention champion, because his work traces the four stages that appear wherever disaster gets averted: recognition, evidence, translation, and implementation.

Recognition: The Familiar Has Become Lethal

The danger is not that the West has never experienced drought. It has. The danger is that the system now has far less protection against another bad year, and that remaining margin is disappearing quickly.

Lake Powell now sits at about 23 percent of capacity, Lake Mead at about 27 percent. Between them, these two reservoirs hold nearly 60% of the water stored in the Colorado River Basin. The Colorado River supplies approximately 40 million people, supports about 5.5 million acres of agriculture, and produces more than 8 billion kilowatt-hours of hydroelectric energy annually, enough for approximately 700,000 homes. These reservoirs function as the Southwest’s reserve capacity, storing water from wetter periods for use during dry ones.

The next danger comes when levels fall so low that Glen Canyon Dam (at the downstream southern end of Lake Powell) can no longer generate electricity. The Bureau of Reclamation’s June 2026 projections showed Lake Powell approaching such a threshold in spring 2027. Prevention failures rarely arrive as taps running dry overnight but instead unfold as cascades. Loss of hydropower and deeper water reductions would affect electricity, agriculture, communities, and other water-dependent uses across the basin.

Evidence: The River Has Changed Faster Than the Rules

The record is harsh. Colorado River flows and reservoir storage have declined during the roughly twenty-five-year drought, with warming, reduced snowpack and runoff, and water demand all contributing to the crisis. The 2026 water year brought the lowest winter snowpack on record in the Upper Basin and record-breaking March heat, further worsening conditions.

The deeper problem is not one bad year of nature. The institutions governing the river still operate within a legal framework created when twentieth-century water supplies were assumed to be more abundant. The 1922 Colorado River Compact apportioned 7.5 million acre-feet annually to each basin. Recent research concludes that consumptive use must fall substantially to stabilize reservoir levels as warming continues to reduce runoff.

The Southwest cannot choose between adapting to the water crisis and confronting the warming that is making it worse. Both tasks are now unavoidable. Adaptation will determine whether the region can manage the crisis already before it. Mitigation will help determine how severe that crisis becomes.

What is most troubling is that the legal and political system built to manage the river has not changed as fast as the river itself. This widening gap is the central prevention failure.

Translation: Hope Is Not a Water Policy

Evidence accomplishes nothing until someone explains what it means, convincingly, to people with power. Schmidt and his colleagues are doing precisely that, translating reservoir measurements into a warning the public cannot ignore. Sarah Porter, director of the Kyl Center for Water Policy at Arizona State University, cautioned that even record snowpack would not move the system out of danger. Schmidt put it more bluntly, saying that hope and prayer are no way to run a national water system.

Yet hope has quietly become part of water policy in the basin. A strong winter may buy time. So may an emergency transfer or another round of voluntary conservation. But this is not the same as recovery. The seven basin states remain divided over how a lasting burden of reductions should be shared. California, Arizona, and Nevada have offered temporary reductions through 2028, and federal officials are preparing to accept much of their proposal. That is movement, but it is not a durable settlement. The long-term operating rules remain unresolved.

Implementation: What Action Actually Looks Like

Household conservation matters, but it cannot carry the burden now facing the Colorado River. Nor can temporary agreements buy another year or two. The basin must use less water, manage the reservoirs more realistically, and reshape agriculture and development for a hotter future. Officials also need conservation rules tied directly to reservoir conditions, so reductions occur predictably instead of through repeated emergency negotiations.

The longer work will require reductions in agricultural water use, crops suited to an arid century, aggressive recycling, and honest scrutiny of development built on water that may never arrive. Tribal nations and rural communities must hold a meaningful seat in these decisions; the river is a vital resource for 30 Tribal Nations, and federal planning calls for continued Tribal consultation. At the same time, reducing greenhouse-gas emissions remains essential, because less mitigation makes adaptation increasingly difficult and can eventually push some systems beyond their ability to adapt.

Catastrophe is not inevitable. The reservoirs are sounding the alarm before complete failure, which is exactly what a prevention system is supposed to do. The river has warned us with that visible bathtub ring on the canyon walls. What happens next is up to the residents of the Colorado River Basin.

For 156 consecutive weeks, I have written about one central idea: prevention matters most before a crisis becomes visible. Substack tells me that this publishing streak is longer than 99.35 percent of its writers. On a platform used by millions of contributors, that is a milestone I never expected to reach.

I am deeply grateful to everyone who has read these essays, shared them, commented on them, or encouraged me to continue. Some of you have been here from the beginning. Others have joined more recently. Every reader has helped make this work feel worthwhile.

As the United States observes its 250th anniversary, I keep returning to the words “life, liberty, and the pursuit of happiness.” Those promises cannot be fully realized without prevention. Life is diminished when preventable disease, injury, violence, or disaster cuts it short. Liberty is threatened when democratic institutions are allowed to erode. The pursuit of happiness becomes far more difficult when individuals, families, and communities are overwhelmed by dangers that could have been anticipated and reduced.

Benjamin Franklin understood that prevention extended far beyond medicine. His famous statement, “An ounce of prevention is worth a pound of cure,” was written about fire. The same principle applies to natural disasters, climate change, democratic backsliding, war, suicide, traffic deaths, pollution, cyberattacks, financial crises, and many other threats.

In each case, the central question is the same. Will we recognize danger and act before the damage becomes undeniable, or will we wait until the cost is far greater?

This past year, the message has traveled farther than I anticipated. My book, The Preventioneers: Diseases, Disasters, and the Discoveries That Changed Our World, has received generous praise from authors, reviewers, and leaders in public health. Its ideas have also led to conversations with audiences across the country through podcasts, television, radio, op-eds, essays, presentations, and book signings.

These experiences have reinforced my belief that people care about prevention when it is presented not only through policy and statistics, but through human stories. The most compelling narratives are often about people who recognized danger early, assembled the evidence, faced resistance, and continued working until action became possible.

To new readers, I am glad you are here. I hope you will explore some of the earlier essays, subscribe, and join me in the year ahead. To longtime readers, thank you for your loyalty, encouragement, and thoughtful responses.

I also appreciate new ideas. Please let me know about people, events, discoveries, or current dangers that you believe should be examined through the lens of prevention. I am especially grateful to fellow authors who have encouraged me along the way. I would be pleased to hear from those who might wish to suggest a topic, contribute an idea, or explore writing an essay together.

Three years in, my purpose remains the same: to make prevention more visible, more understandable, and harder to ignore.

George Orwell, 1943

The title sounds strange at first. Orwell was not writing primarily about the banning of books after authors had written them. He was describing something deeper, the destruction of the intellectual freedom that writers need before they can write honestly.

Orwell wrote that freedom of the intellect meant the freedom to report “what one has seen, heard, and felt." He focused on writers, journalists, and intellectuals, but his argument also applies to public health, medicine, environmental science, and prevention.

Prevention begins with observation. Scientists and public health professionals count infections, deaths, injuries, exposures, blood pressures, temperatures, emissions, and changes over time. Before society can prevent harm, someone must identify the danger, document the evidence, and discuss what the evidence shows.

Our security and prosperity depend on our willingness to heed timely warnings. Climate change provides one of the clearest contemporary examples. The warning did not come from one storm, flood, wildfire, or scientific paper. It emerged from decades of measurements that documented rising concentrations of greenhouse gases, increasing global temperatures, warming oceans, melting ice, rising seas, and other changes in the Earth’s climate system.

Scientists have provided abundant evidence. The greater problem has been the persistent resistance to what that evidence requires us to acknowledge and do.

The same pattern runs throughout the history of prevention. Ignaz Semmelweis examined the striking differences in maternal mortality between two obstetric clinics, and he reduced deaths by requiring physicians and medical students to wash their hands with a chlorinated solution. Researchers later compared the smoking histories of people with lung cancer with those of people without the disease, and they followed large groups of people over time. Their studies helped establish the relationship between cigarette smoking and lung cancer.

In each case, the evidence threatened an established interest. The findings challenged professional authority, commercial power, accepted habits, political priorities, or reassuring assumptions. Evidence did not protect the public merely because the evidence existed.

People had to collect the information, preserve it, interpret it honestly, and communicate it clearly. They also had to continue speaking when their findings met resistance.

That is why recent disputes over the availability of federal health information deserve attention. In early 2025, several major federal health surveys, databases, and dashboards became unavailable. Some resources later returned, but the episode showed how quickly researchers, policymakers, journalists, and members of the public can lose access to important information.

Every administration changes policies, priorities, terminology, and government websites. Scientists also revise measures and datasets when new evidence or better methods become available. Those normal processes differ from removing information because the information, or its implications, has become politically inconvenient. Proposed revisions from the Office of Management and Budget would allow political priorities to play a larger role in federal research awards. They could permit agencies to terminate ongoing grants that no longer align with administration priorities. That would amount to something close to the prevention of science itself.

Orwell wrote that a journalist becomes unfree when he must “suppress what seems to him important news.” A related problem arises when an agency stops collecting important information, when a scientist hesitates to report an unwelcome result, or when evidence becomes difficult for the public to find.

Orwell’s argument does not require us to label every disputed decision as authoritarian. His warning concerns a habit of mind. It develops when people judge evidence by whether it helps their political side instead of whether it accurately describes reality.

The people I call preventioneers resisted that habit. They recognized dangers before society was ready to act, and they insisted that inconvenient evidence still deserved attention. Their first contribution was often not a treatment, regulation, or public program. Their first contribution was the willingness to state clearly what they had observed.

Orwell called his essay “The Prevention of Literature” because literature can be stopped before anyone formally prohibits a book. Writers can stop themselves when they suppress their observations, repeat approved formulas, or avoid conclusions that they fear they should not express.

Prevention can fail in the same way. It can fail when society stops measuring a danger, when officials make evidence inaccessible, or when professionals decide that speaking plainly carries too great a cost.

Orwell warned that “a bought mind is a spoiled mind.” Public health and climate science require minds that remain free to examine evidence, question accepted positions, and tell the public what the evidence shows.

Explore The Preventioneers

Most Americans picture the Declaration of Independence as a single event wherein fifty-six men gathered in Philadelphia on July 4, 1776, placing their names on parchment. It did not happen that way. No delegate signed the famous parchment that day.

On July 2, the Continental Congress voted for independence by approving the Lee Resolution. Two days later, Congress adopted the final text of the Declaration, the statement that announced and justified the break with Britain through a philosophy of government and a list of grievances against the Crown.

Printer John Dunlap then worked through the night to produce the first printed copies. These large, single-sheet printings became known as the Dunlap Broadsides. Congress sent them to committees, assemblies, and military commanders so the Declaration could be circulated and proclaimed. They did not carry the fifty-six handwritten signatures.

On July 19, Congress ordered the approved text copied in a formal hand onto parchment. Most delegates began signing that document on August 2, and others added their names later. Eventually, fifty-six men signed it. This is the famous document now preserved at the National Archives.

By August 2, a new member had joined the Pennsylvania delegation. His name was Benjamin Rush. Pennsylvania selected a new delegation on July 20, Rush took his seat on July 22, and eleven days later, he signed the parchment Declaration. Rush deserves attention not only as a signer, but also as an early and deeply complicated prevention pioneer or preventioneer.

Rush was born on a farm about 14 miles outside of Philadelphia in 1746. He studied medicine in Edinburgh, practiced and taught medicine in Philadelphia, and served in the Continental Army’s medical department. He also became active in education, temperance, abolition, and the early history of mental health. Rush was one of four physicians who signed the Declaration. The others were Josiah Bartlett, Lyman Hall, and Matthew Thornton.

Why did Rush sign? He had supported separation before he entered Congress. Rush encouraged Thomas Paine as Paine developed the pamphlet that became Common Sense, and historical accounts credit Rush with helping find a publisher and suggesting the title.

But Rush is interesting for another reason. His story follows the four stages of prevention: recognition, evidence, translation, and implementation.

Recognition

During the Revolutionary War, the most obvious danger to a soldier was combat. Rush saw another enemy. In a document he would later publish, he wrote,

Fatal experience has taught the people of America the truth... that a greater proportion of men perish with sickness in all armies than fall by the sword.

Rush identified dangers that could be changed before illness appeared. He urged soldiers to change clothes and socks, eat more vegetables, drink less alcohol, wash regularly, replace the hay they slept on, dry blankets in the sun, keep filth away from tents, and avoid unnecessary fatigue. Prevention often begins when someone notices harm that others have learned to accept as normal.

Evidence

Rush practiced before germ theory, modern epidemiology, randomized clinical trials, or the statistical methods that guide medicine today. He relied on observation, experience, clinical patterns, and the medical theories of his time. His military recommendations show the power of careful observation, but his later career also shows its limits.

During Philadelphia’s 1793 yellow fever epidemic, Rush strongly promoted bloodletting and purging. Those treatments became deeply controversial, and modern historical accounts describe the harm and criticism associated with his methods. A physician can recognize a real danger and still promote the wrong remedy when confidence outruns reliable evidence.

Translation

Rush did not keep his ideas inside the medical profession. In 1777, his advice on preserving soldiers’ health appeared publicly, and a 1778 pamphlet, Directions for Preserving the Health of Soldiers, addressed officers directly. He turned medical observations into practical instructions for the people who could act on them.

That step still challenges us today. Evidence accomplishes little unless someone translates it into guidance that people can understand and use.

Implementation

Rush pushed prevention beyond advice to individual soldiers. By addressing officers, he treated the preservation of health as a leadership responsibility, not simply a physician’s task after illness appeared. He argued that commanders had a duty to save the lives of their men.

Benjamin Rush was not a flawless hero of prevention. He was something more interesting because he recognized preventable harm, searched for evidence, translated ideas into practical guidance, and tried to put those ideas into practice. His successes showed the power of prevention, while his failures showed why evidence and humility matter.

Franklin understood that fires, disease, and other hazards were not only private misfortunes. They were shared risks requiring shared action. That insight still matters, especially at a time when many of our greatest challenges are easiest to address before they become crises.

The themes explored in this op-ed in The Hill are more fully developed in my book, The Preventioneers: Diseases, Disasters, and the Discoveries That Changed Our World.

Those words deserve to be celebrated. But there is another way to look at over two centuries of American history. We can ask not only what the country declared, built, invented, or won, but what it learned to prevent.

Prevention is one of the quiet measures of national progress. It does not always announce itself dramatically. Often it appears in the background of ordinary life, in dangers reduced, deaths delayed or avoided, injuries made less likely, and risks that no longer seem as unavoidable as they once did.

In the Revolutionary era, smallpox threatened armies and communities. George Washington’s decision in 1777 to inoculate the Continental Army against smallpox was a strategic and preventive act. It recognized that disease could weaken an army as surely as enemy fire. Benjamin Rush, a physician and signer of the Declaration, made a similar point when he urged officers to protect soldiers from sickness, exhaustion, poor diet, and unhealthy camp conditions. Even at the beginning of the country, prevention was not an abstraction. It was a matter of survival.

Smallpox and the American Revolution

That pattern continued across American life. Again and again, people looked at familiar tragedies and asked whether they truly had to continue. Did infants have to die in such large numbers? Did workers have to accept injury as the cost of earning a living? Did drivers and passengers have to die because vehicles and roads were designed with too little attention to human survival? Did patients have to suffer preventable infections? Did tobacco-related disease, uncontrolled high blood pressure, unsafe water, or environmental hazards have to be treated as unavoidable?

The answer, again and again, was no. But that answer was rarely accepted quickly.

Prevention seldom begins with consensus. It often begins with recognition. Someone sees a pattern that others have accepted as normal. Someone gathers evidence. Someone translates that evidence into practice. Someone fights for implementation through laws, institutions, habits, engineering, medicine, or public trust.

Over time, those efforts changed the country. Vaccination, clean water, safer food, safer workplaces, motor-vehicle safety, healthier mothers and babies, fluoridated water, tobacco control, blood pressure treatment, and reductions in deaths from heart disease and stroke all changed the odds of ordinary life. They did not eliminate suffering, and they did not make the country perfect. They made many once-routine tragedies less common.

That may be the central point. Prevention is not only a medical idea. It is a civic achievement. It requires evidence, but also trust. It requires science, but also translation. It requires individual responsibility, but also systems that make safer choices possible.

As America approaches 250 years, we will rightly celebrate independence. But we might also remember the less visible work that allows freedom to be lived in daily life: safer homes, safer roads, safer workplaces, cleaner water, better vaccines, healthier children, and fewer preventable deaths.

That is why prevention belongs in the American story. Not as a slogan, and not as a partisan claim, but as one of the practical ways a society protects life, preserves liberty, and gives more people the chance to pursue a meaningful future.

Prevention often begins with objects so ordinary that we stop seeing them: a fire bucket, a basin, a seat belt, and a sign on a bridge. Each one looks simple by itself, but each points to a larger story about danger seen early, evidence resisted, and lives that might be saved before harm becomes unavoidable.

A fire bucket is not usually thought of as a revolutionary object. But in a crowded city of wooden buildings, where one spark could threaten an entire neighborhood, it carried a civic idea. It asked people to prepare before the flames appeared. It suggested that safety was not only a private concern but a shared responsibility.

A basin is even simpler. It belongs to the ordinary world of washing, cleaning, and care. Yet in one of the most painful stories in the history of medicine, something as simple as washing became the center of a struggle over evidence, authority, pride, and the lives of mothers. Sometimes prevention is difficult, not because the act itself is complicated, but because people resist what the act implies.

A seat belt seems almost invisible now. We fasten it without thinking, or at least we should. But it represents a profound change in how people came to think about injury. The question was no longer only why crashes happened. It was also whether the human body could be protected when they did. That shift, from blaming the victim to redesigning the environment, is one of the central insights of prevention.

A sign on a bridge may be the quietest object of all. It does not cure disease, stop a car, or put out a fire. It simply appears at a place where a person may be in danger and says, in effect, help is possible. It reminds us that prevention can be immediate, concrete, and humane. Sometimes the distance between despair and survival is measured in seconds, words, and whether help is visible.

These objects stayed with me while I was writing The Preventioneers because they show that prevention is not only an idea, a policy, or a scientific finding. It is also something people build, carry, install, and use before the worst happens.

Together, these four objects suggest the range of the book: a neighborhood before a fire, a hospital before infection, a body before injury, and a person before a fatal act. They do not look heroic, but in the right place, at the right time, each can become part of a story about lives saved before they are lost.

That is the world of The Preventioneers. Ordinary objects can have extraordinary consequences when people recognize their power to prevent harm before it is too late.

Visit My Website

Last week, I wrote about the books behind The Preventioneers, the works that shaped the people in its pages and helped them see the world differently. This week, I want to turn from books to places.

Prevention can sound abstract. We talk about evidence, risk, policy, behavior, and systems. Still, the stories in The Preventioneers happen somewhere: in a hospital ward, in a tenement apartment, on a desert test track, or on a bridge. In each place, someone saw danger before others were ready to act.

One place was a maternity ward in nineteenth-century Vienna. Women entered expecting to give birth, but too many never left. The danger was hidden in plain sight, in the hospital’s daily routines. What happened there became one of the most painful and important stories in the history of medicine, not only because of what was discovered, but because of how fiercely that discovery was resisted.

Another place was New York City, not the New York of skyscrapers and postcards, but the crowded tenements where babies died by the thousands. The causes were not mysterious to the families living there. They were heat, poverty, unsafe milk, overcrowding, and neglect. But it took a remarkable public health physician to enter those neighborhoods, listen, organize, and prove that children did not have to die simply because they were born poor.

A third place was a rocket sled track in the New Mexico desert. It seems almost absurd at first, a man strapping himself into a machine built to stop violently at high speed. But that place helped change how people thought about crashes. The question was not only whether accidents would happen, but whether cars, roads, and safety systems could be designed so that people might survive them.

Then there were the bridges and cliffs, beautiful places that could become sites of despair. These were among the most haunting settings in the book. They showed that prevention is sometimes immediate, personal, and concrete. A barrier, a sign, a phone, a patrol, or one human being willing to stay nearby can become the difference between life and death.

These places stayed with me while I was writing The Preventioneers because they remind us that prevention is not only an idea, a study, a guideline, or a policy. It is a choice made in the real world, before the infection, before the living conditions, before the crash, and before the jump.

The book travels to other places, too. Places like colonial cities, clinics, laboratories, public hearings, and rooms where evidence had to fight for attention. But the pattern is often the same. Someone sees danger early. Others doubt, delay, or resist. Then the question becomes whether action will come soon enough.

That is the story I wanted to tell in The Preventioneers: not only the science of prevention, but the places where it became real.

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When Benjamin Franklin was a boy in Boston, he later wrote, “all the little money that came into my hands was ever laid out into books.” A favorite was Daniel Defoe’s An Essay Upon Projects, which proposed civic schemes for everything from insurance to the care of widows. Years later, when Franklin organized America’s first fire companies and pressed his neighbors to think about prevention rather than ruin, the ideas a book had planted were still at work.

That pattern repeats across The Preventioneers. Again and again, the people who saw a preventable harm coming were readers first. Some were shaped by the books they read; others left behind books of their own. As one small thank-you to everyone who has picked up The Preventioneers this month, here is the shelf behind it showing the books named in its pages, and why each one earned a place.

The books that shaped them

A surprising number of the preventioneers can trace their calling to something they read. Edward Freis, who proved that treating high blood pressure saves lives, fell in love with medicine through Paul de Kruif’s two classics of popular science: Microbe Hunters, with its chapter on Paul Ehrlich and the search for a “magic bullet,” and Hunger Fighters, which told the story of Joseph Goldberger linking pellagra to diet. De Kruif’s gift was making discovery feel like adventure, exactly the spirit I hoped to carry forward.

Franklin, as noted, read Defoe, including An Essay Upon Projects and A Tour Through the Whole Island of Great Britain, which shaped how he saw the growing cities he would later try to make safer. And the proverb that gives the whole book its spine, an ounce of prevention is worth a pound of cure, has roots in Adagia, Erasmus’s vast sixteenth-century collection of Greek and Latin sayings.

James Hansen, the climate scientist, sharpened his public voice in part by arguing with a book he thought got the science wrong: Michael Crichton’s novel State of Fear. He also lent his name to Keith Farnish’s Time’s Up! Sometimes a book matters because of how hard you push back on it.

The books they wrote

Many preventioneers did not stop at doing the work. They wrote it down, often against indifference.

Benjamin Franklin left behind one of the most enduring American life stories in The Autobiography of Benjamin Franklin, a book that turned self-improvement, civic duty, and practical wisdom into inspiration for generations of readers. Ignaz Semmelweis, who begged physicians to wash their hands, finally set out his case in The Aetiology, Concept, and Prophylaxis of Childbed Fever, five hundred pages that were largely ignored in his lifetime and vindicated only after his death. Sara Josephine Baker, who drove down infant mortality in New York’s tenements, was extraordinarily prolific, writing five books about babies, children, and mothers, plus a memoir, Fighting for Life, whose title says everything about what public health cost her.

Colonel John Stapp, the “fastest man on earth” whose body absorbed crash forces so that drivers wouldn’t have to, self-published a book of verse, For Your Moments of Inertia: From Levity to Gravity, intending one poem to serve as his epitaph. Kevin Briggs, who talked hundreds of people off the Golden Gate Bridge, told his story in Guardian of the Golden Gate. John Tyndall, who understood more than a century ago that certain gases trap the sun’s heat, described that “blanket” of the atmosphere in Radiant Heat. James Hansen would later write Storms of My Grandchildren.

The books that named the problem

A few titles appear because they named a danger plainly when others looked away. John Spargo’s The Bitter Cry of the Children put the cost of poverty in front of a comfortable public. Naomi Oreskes and Erik Conway’s Merchants of Doubt anatomized how the tobacco industry, and later others, manufactured uncertainty to delay action. Joel Eastman’s Styling vs. Safety documented an auto industry that chose appearance over lives for decades. Also, the medical reference shelves of their eras, Paul Martini’s Methods of Therapeutic Investigation, the Cecil-Loeb Textbook of Medicine, the great pharmacology and clinical texts, quietly recorded how slowly even good evidence becomes standard care.

Why it matters

There is a thread running through this shelf. Prevention has always depended not just on discovery but also on communication and on someone willing to write the warning down, argue for it, and keep arguing after the science was settled. Franklin published. Semmelweis published. Baker published. Hansen published. The evidence rarely speaks for itself; someone has to speak for it.

That is really what The Preventioneers is about, and it’s the thread The Scientist drew out in its recent feature on the book. If any of these titles are new to you, I hope you’ll seek one out. If you’d like the whole story of how readers and writers became reformers, The Preventioneers is here.

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In March 2000, Katie Couric allowed millions of Americans to watch something most people would rather avoid: a colonoscopy. Her husband, Jay Monahan, had died of colon cancer, and Couric used morning television to turn private grief into public prevention. The response became known as the “Katie Couric Effect,” after researchers found that colonoscopy use rose more than 20 percent following the broadcast. It was an unusual television moment, but it carried a simple message. Screening can find danger before the disease becomes deadly.

Her campaign reached millions, but persuasion is not evidence. Someone still had to ask the practical question of whether screening actually prevents death. In 2002, the U.S. Preventive Services Task Force answered it. After reviewing the evidence, the Task Force recommended that adults age 50 and older be screened for colorectal cancer, and later guidance expanded screening to adults ages 45 to 75. Screening could find cancer early, when treatment works best, and remove precancerous polyps before they turn into cancer. That is prevention at its best, action before advanced cancer, before emergency surgery, before a family asks whether something could have been done sooner.

The Task Force was created to make those judgments carefully and consistently. It was first convened in 1984 and published its first Guide to Clinical Preventive Services in 1989, with program support later moving to the Agency for Healthcare Research and Quality. That is the machinery by which evidence becomes action and can be lifesaving.

The Task Force is an independent group of national experts in prevention and evidence-based medicine. It reviews screening tests, counseling, and preventive medications, grading each by the certainty and magnitude of net benefit, the expected benefit after harms are weighed. An A recommendation reflects high certainty of substantial benefit, a B reflects high or moderate certainty of moderate benefit.

Those grades matter beyond the exam room. Under Section 2713 of the Affordable Care Act, many private insurers must cover services that earn an A or B recommendation without deductibles or co-pays. They are not merely academic. They shape what patients receive, what clinicians recommend, and what insurers cover.

But prevention is not as simple as doing more. Screening can save lives, and screening can also cause harm. The Task Force judges every service by the balance of benefits and harms, not by benefit alone. Those harms can include false positives, unnecessary biopsies, overdiagnosis, and overtreatment. Its job is to resist the slogan that more medicine is always better, and to ask the harder questions. What helps, for whom, at what age, how often, and at what cost in harm?

That is why some recommendations have been controversial. Breast and prostate cancer screening, aspirin, and lung cancer screening all demand judgments about benefit, harm, age, and uncertainty. A recommendation to screen earlier can save lives. A recommendation to screen less often can also protect people when the evidence shows harms beginning to outweigh benefits. That is hard to explain in a culture that equates action with care.

The deeper lesson is that evidence does not implement itself. It must be gathered, judged, translated, communicated, trusted, and acted upon. Between the first warning and the final policy lies a long and fragile chain. If any link breaks, prevention fails.

That chain is now under strain. In May 2026, Health and Human Services (HHS) Secretary Robert F. Kennedy Jr. removed the two leaders of the Task Force, Dr. John Wong and Dr. Esa Davis, before their terms had ended. HHS called the move administrative and said it was meant to protect the integrity of the panel’s work. But the surrounding facts are more troubling. Two former leaders wrote that Kennedy had postponed meetings, blocked new topics, and shelved new recommendations, including cervical cancer screening guidance.

The panel’s makeup makes this especially important. The Task Force has traditionally had 16 independent, volunteer experts. After the removals and earlier vacancies, many seats sit unfilled, raising the possibility that the panel could be substantially reshaped before future recommendations are issued. That makes this more than a personnel dispute. It raises the question of whether one of the country’s most important evidence-review bodies will stay independent enough to be trusted.

That matters because prevention depends not only on evidence but on trust. Clinicians must believe that recommendations are scientific judgments, patients that they are not political products, and insurers and policymakers that the process is legitimate. Once that trust weakens, the damage is not confined to one committee. It can spread to cancer screening, blood pressure control, depression screening, and many other quiet acts that keep people from becoming patients.

No expert panel is perfect, and its judgments must be reassessed as evidence and disease patterns change. But the alternative is worse. Without a trusted evidence process, preventive care is driven instead by marketing, politics, habit, and wishful thinking. Weakening the independence of such a body is no minor administrative matter.

Whatever one’s politics, the stakes are clear. If recommendations become less trusted, patients suffer. If proven recommendations are rolled back, people may lose access to services that catch disease early and lower the risk of an adverse outcome.

This work is not glamorous. But prevention rarely announces itself with drama. Its victories are measured in cancers not advanced, strokes not suffered, heart attacks avoided, and families spared a diagnosis that came too late. The Task Force is one of the institutions built to make those quiet victories possible. Its work deserves scrutiny, because all powerful institutions do. But it also deserves protection, because without trusted evidence, prevention becomes just another political argument, and patients pay the price.

The Preventioneers tells the stories of the people who saw danger coming — and acted before catastrophe became inevitable.

Much has changed since then. We can measure blood pressure easily. We have effective medicines. Many are generic and inexpensive. We have decades of evidence showing that lowering blood pressure saves lives and prevents disabling cardiovascular and kidney complications. Yet the story remains unfinished.

High blood pressure is still called the silent killer. The phrase is accurate, but maybe too gentle. Hypertension usually causes no symptoms. It does not arrive as an outbreak. It does not create a memorable image. It raises pressure inside arteries slowly, day after day, year after year, until the damage appears in the brain, heart, kidneys, or blood vessels.

Rare infections get attention. A case of hantavirus, a cluster of bird flu, or a new virus in the news feels sudden and frightening. These threats deserve serious public health attention. But they also show how we respond to danger. We notice what is visible and immediate, while the larger, quieter threats often fade into the background.

May 17 was World Hypertension Day. It passed with far less attention than the problem deserves. Hypertension is the leading preventable risk factor for premature death worldwide. Yet only about one in five people with hypertension globally and in the United States have controlled blood pressure, even though effective generic medicines are available. Many people with uncontrolled hypertension are not taking any blood pressure medication at all.

This is astonishing. We know how to measure blood pressure and how to treat it when it is elevated. Medications are not expensive, and treatment guidelines are clear. Yet most people with hypertension are not controlled. This is not mainly a failure of discovery. It is on of follow-through.

A person can have insurance, see a clinician, have blood pressure measured, and remain untreated or undertreated. An elevated reading may lead to “let’s recheck next time.” Follow-up may be months away. Home blood pressure readings may never enter the medical record in a useful way. Medication adjustment may depend on whether a busy clinician has enough time during a short visit. Copays, pharmacy access, short refills, and fragmented care can make long-term control harder than it should be.

In that kind of system, inaction becomes the default. No one has to make a dramatic mistake. The patient is seen, the blood pressure is recorded, advice is given, and the chart is closed. But the risk remains, and the body continues to experience the burden of elevated pressure.

There is also a clinical trap. A patient may have a systolic blood pressure of 145 or 150 and feel perfectly well. The number is elevated, but not alarming. The patient may already be taking one medicine. Everyone has the impression that things are stable, but stable is not the same as protected.

Risk can accumulate silently for years before it appears as a medical crisis. The body does not care that a number seemed only mildly elevated at a visit. Blood vessels, the heart, the brain, and the kidneys experience the cumulative burden. A blood pressure reading is a warning. Too often, it becomes just another number in the chart.

The answer has to move upstream. But upstream does not mean simply telling people to eat better, exercise more, and use less salt. Those things matter, but advice alone is not a prevention system. Moving upstream means changing the conditions that produce risk and the systems that respond to risk.

That starts with reducing sodium in the food supply rather than simply blaming people for consuming too much of it. It requires routine blood pressure checks, affordable medications, and primary care systems that treat an elevated reading as a warning to be acted on, not a number to be filed away.

One country that shows the power of this approach is South Korea. Its success was not the result of a single breakthrough drug or public awareness slogan. It combined clinical care with national policy, expanding hypertension detection and treatment while also pursuing population-wide sodium reduction through schools, restaurants, food manufacturers, public campaigns, and nutrition monitoring. In 2012, South Korea launched a national sodium reduction plan that aimed to cut population sodium intake by 20 percent; by 2014, adult sodium consumption had fallen by almost 24 percent compared with 2010 levels, with reported declines in population blood pressure and hypertension prevalence. The larger health trends were striking: from 1990 to 2021, South Korea had the largest decline in age-standardized stroke mortality among China, Japan, the U.S., and South Korea, with reductions of 82 percent in men and 84 percent in women. The lesson is not that every country can copy South Korea exactly. It is that hypertension control improves when prevention is built into routine care, food policy, financing, and follow-up.

The World Health Organization’s Global HEARTS Initiative applies the same logic at a broader scale. Launched in 2016, Global HEARTS aims to improve cardiovascular prevention, detection, and control through practical primary-care tools: standardized treatment protocols, reliable access to essential medicines and validated blood pressure devices, team-based care, patient-centered services, and information systems that track control. By December 2024, these programs had started about 34 million people on treatment in more than 220,000 primary-care facilities across 38 countries. In Bangladesh, a quasi-experimental evaluation found better blood pressure control in HEARTS intervention facilities after six months, 62 percent versus almost 50 percent, with systolic blood pressure 3.7 mm Hg lower than in usual-care facilities. These are not glamorous interventions. But they are the machinery of prevention.

A serious response would make blood pressure control a default function of care. Every adult should have their blood pressure measured accurately. Every uncontrolled reading should trigger a closed-loop pathway: confirm it, treat it, follow up within weeks, adjust treatment when needed, and track the patient until control is achieved. The response cannot stop at the clinic door. Sodium reduction, affordable medications, pharmacist- and nurse-led care, home monitoring, better data systems, and payment models that reward control all belong in the same prevention strategy.

None of this has the drama of a rescue. But ordinary tools, used reliably, are how prevention becomes real. They turn a warning number into action before the ambulance, the intensive care unit, or the funeral.

More than 80 years after Roosevelt’s death, the victory over hypertension is much closer than it was. But it is not complete. The silent killer does not need a new name. It needs a louder system, one that moves upstream, acts early, and follows every warning until blood pressure is controlled.

MV Hondius

WHO has assessed the public health risk as low, and that assessment is almost certainly correct. Hantaviruses do not behave like influenza or COVID-19, and the Andes virus has caused only limited person-to-person spread in the past. This will not be the next pandemic. But the Hondius story still matters, and not for the reason most people will read it.

Hantaviruses are not exotic. Rodents carry them, and humans pick them up by breathing air contaminated with rodent urine, droppings, or saliva. What is unusual here is geography and motion. Investigators believe two of the deceased may have caught the virus before they boarded, during weeks of bird-watching across Argentina, Chile, and Uruguay in regions where the rodent that carries Andes virus is endemic. The precise site of infection is still under investigation, and health officials in Buenos Aires have pushed back on early reports pointing to a landfill near Ushuaia. Within weeks, that local origin produced an international response touching passengers from 23 countries. That is what modern biological risk looks like.

Argentina itself is already living this story. Hantavirus cases there have nearly doubled in the past year, with 101 confirmed infections and 32 deaths so far this season. That is the country’s highest count since 2018. The disease used to cluster in Patagonia. This year it is appearing farther north, in the central provinces, as the long-tailed mouse that carries the virus moves into territory reshaped by drought, intense rainfall, and forest fires. Argentine health officials name climate change and habitat destruction directly.

Scientists estimate that mammals and birds harbor roughly 1.7 million viruses we have never described, of which between 540,000 and 850,000 may be capable of infecting humans. We have catalogued less than one-tenth of one percent of that pool. Warmer climates, expanding land use, and global travel are bringing more of the unknown into contact with people every year.

The standard public health response waits for illness to appear. A clinician identifies a patient, a laboratory confirms the pathogen, health officers trace the contacts, and treatment starts. That work saves lives, but it is not enough. Prevention has to begin earlier. It means watching wildlife and the environments they share with people. It means safer land use and strong local health departments, in place before crises arrive. It means honest international reporting, so that a cluster on a Dutch-flagged ship reaches the right desks within hours, not weeks. It means treating climate policy as health policy.

The boundary between human health and the natural world is more porous than we like to imagine. By the time a danger is obvious, the most useful window for action has usually closed. The viral world is vast, and most of it is unknown to us. That is why prevention matters.

An advisory committee convened by NHLBI had flown in to review the data from a 42,000-patient hypertension trial. I was there to present it.

The trial was ALLHAT — the Antihypertensive and Lipid Lowering Treatment to Prevent Heart Attack Trial — and we had been comparing four blood-pressure medications head-to-head. By that January, the evidence on one of them, the alpha-blocker doxazosin, was no longer ambiguous. Compared with the diuretic chlorthalidone, doxazosin did not prevent heart attacks any better. On a secondary outcome, the rate of heart failure was running roughly twice as high.

The committee read the data. We talked it through. The recommendation was made and transmitted to the Director of NHLBI, who accepted it.

What followed was procedural and, in its own way, the harder part. More than forty-two thousand letters went out to participants. Six hundred twenty-eight clinics had to be notified. Three hundred thirteen institutional review boards had to be informed. A JAMA paper followed, accompanied by an embargoed press release and a late-breaking presentation at the American College of Cardiology. In the years after, hypertension guidelines were rewritten. Alpha-blockers were no longer recommended as first-line therapy. Diuretics were reaffirmed.

Across a career in clinical trials and prevention science — HDFP, SHEP, ALLHAT, SPRINT — I have watched evidence move toward action. Sometimes that movement happens quickly. Other times it does not happen at all. Often it happens, but later than it should.

Today, The Preventioneers: Diseases, Disasters, and the Discoveries That Changed Our World is officially out. I wrote this book to explore a question that has stayed with me for much of my career: Why do we so often delay action on increasingly visible dangers?

Again and again, history follows a familiar pattern. Someone sees a threat early. Evidence begins to accumulate. Yet action comes slowly. By the time the response arrives, much of the damage has already been done. That pattern runs throughout this book.

Benjamin Franklin understood that cities could prepare for fire before catastrophe struck. Ignaz Semmelweis showed that handwashing could save the lives of mothers long before medicine was ready to accept what he had seen. The pioneers of auto safety made the case that crashes did not have to be so lethal. Researchers studying smoking and lung cancer helped reveal one of the great preventable causes of death in modern life.

These stories are about discovery. But they are also about resistance, delay, and the difficulty of turning knowledge into action. That is one reason these histories feel so relevant now.

We are living through another age of warnings. Climate change is no longer a distant scenario. Its effects can be seen in heat, wildfire, flooding, and other threats to health and daily life. The evidence has been building for decades. So have the consequences.

The same is true, in a different way, for social media and smartphones. Concerns about their effects on children and adolescents did not appear overnight. Parents, teachers, clinicians, and researchers have been raising questions for years about attention, sleep, anxiety, depression, and what happens when powerful technologies are designed to capture more and more of young people’s time and mental space.

And now AI is raising another set of questions. It is moving quickly into everyday life while society is still struggling to think clearly about safety, transparency, misinformation, concentration of power, and the pace of disruption. Whatever one thinks about its promise, it would be a mistake to assume that prevention can wait until the harms are unmistakable.

Although they are different issues, they have the same challenges.

The difficulty is rarely that no one noticed. More often, someone did. The difficulty is that acting early is hard. It asks for judgment before certainty is complete. It asks institutions to respond to accumulating evidence rather than visible catastrophe. It asks us to take seriously the harms that have not yet fully arrived. That is what prevention demands.

It asks us to care about what does not happen. The fire that never starts. The disease that never develops. The injury that never occurs. The crisis that is reduced before it fully unfolds.

Those outcomes rarely feel dramatic in the moment. They do not command headlines the way disaster does. But they matter enormously. Much of the safety and health we now take for granted exists because someone, somewhere, took prevention seriously before the wider world was ready to do so. That is the spirit behind The Preventioneers.

I wanted to tell the stories of people who recognized danger early and tried to narrow the distance between warning and response. Some are well known. Others should be better known. What they shared was not a profession or ideology, but a willingness to act before the cost of delay became unbearable. I also wanted the book to show that prevention is not a side issue. It sits at the center of how societies protect life.

We often celebrate rescue, treatment, and recovery, and rightly so. But the quieter work of prevention deserves equal respect. It saves lives, reduces suffering, and spares loss on a scale that is easy to underestimate precisely because its successes are often invisible.

If there is one lesson that runs through these pages, it is that delay is not neutral. Waiting has consequences. The interval between warning and response is often where preventable suffering takes root.

We often say, after a crisis, that we saw it coming. History suggests that someone usually did. The more important question is whether we will learn to listen sooner.

The Preventioneers is out today.

Between August 2023 and October 2024, Cedar Key was struck by four hurricanes — Idalia, Debby, Helene, and Milton. The town’s clam industry was wiped out. After living through three of them, the resident reflected:

I’m afraid that decisions are being made for me by consequences of nature, consequences of man’s influence on nature, so that now the place that I had chosen to live may be uninhabitable in my lifetime.

He calculated correctly. The baseline no longer applies.

That sentence is one reason I wrote The Preventioneers. Today, this book feels more urgent than when I wrote it.

Climate change is a chronic crisis with acute flashpoints. Its chronic nature diffuses the urgency that decisive action requires.

Almost forty years ago, a NASA scientist stood before the United States Senate Committee on Energy and Natural Resources and said something that should have changed everything.

It was June 23, 1988. The scientist was James E. Hansen, then director of NASA’s Goddard Institute for Space Studies. His testimony was direct. The Earth was warmer than at any time in the history of instrumental measurements. The warming could now be attributed, with high confidence, to the greenhouse effect. The effect was already large enough to influence the probability of extreme weather events.

Hansen was right. Each of his predictions came true. The costs of delay would prove profound and increasingly irreversible.

We did not act on his warning at a sufficient scale or pace.

Why not? The evidence was strong then and stronger today.

We know what we burn and how much carbon dioxide we emit. We know that burning carbon-based fuel releases CO2 into the atmosphere. We know, from ice cores, that current atmospheric concentrations have not been seen in nearly a million years. We know, from chemical analysis, that the rising CO2 is coming from fossil fuels. We know, from basic physics, that CO2 absorbs heat. We know that warming is melting ice, raising seas, and intensifying storms. We know our climate models match observations. We know there is overwhelming scientific consensus that the change is human-induced and ongoing.

We know all of this, yet knowing has not been enough.

That is one of the themes at the center of The Preventioneers. The book traces stories across three centuries — fire in colonial Philadelphia, childbed fever in nineteenth-century Vienna, infant mortality in tenement New York, automobile injury, hypertension, lung cancer, suicide, and climate change — and finds the same pattern recurring across all of them. Prevention fails not in a single place. It falters when the recognition gap keeps danger invisible, the evidence gap keeps harm contested, the translation gap keeps knowledge from becoming action, and the implementation gap keeps responsibility from becoming routine.

Climate change is the rare case where recognition closed early. Hansen recognized it in 1981 and named it before the Senate in 1988. Evidence has been overwhelming for two decades. The failure has been at the third and fourth gaps of translation and implementation.

That failure, repeated across history, is what the book is about and what makes it matter now. In the spring of 2026, the same pattern is visible on multiple fronts at once. Measles cases in the United States have climbed to their highest level in more than thirty years. A Los Angeles jury has found Meta and YouTube liable for harms to adolescent users that their own internal data had documented for years. The United Kingdom is moving to prevent a new generation from becoming addicted to nicotine before the addiction takes hold. And the climate clock keeps running. The gap between knowing and acting is not a footnote in public health history. It is the central drama of public health history.

The Preventioneers publishes on May 5. It is a book of eight chapters and more than a dozen individuals. Some of these closed the gap in their own time, and some didn’t live long enough to see it close. In our time, the gap is open on multiple fronts, and on the largest one, the clock has been running for nearly forty years.

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As of April 16, the United States recorded 1748 confirmed measles cases in 2026. In 2025, a total of 2,288 confirmed measles cases were reported, the highest number since 1991. Three people died, two children and one adult, all unvaccinated. Canada lost its measles elimination status last November. The United Kingdom, Austria, and Spain followed in January 2026. The Pan American Health Organization will review the United States’ status this November, and it could be revoked. The cause is not mysterious. Measles-Mumps-Rubella (MMR) vaccination coverage among kindergarten students has slipped from 95 percent before the pandemic to 92.5 percent today. If vaccination drops below this threshold, outbreaks return.

During my career, I have watched this pattern play out again and again, in different fields. The evidence linking tobacco to lung cancer was clear by the 1950s, and the Surgeon General’s report did not arrive until 1964. The climate warnings began in the 1970s; James Hansen testified before Congress in 1988, and we are still arguing about the pace of response almost forty years later. COVID-19 exposed the same failure in real time. Pandemic preparedness plans had been written, shelved, and re-shelved for two decades before 2020, and the country spent the early weeks of the crisis relearning lessons that had already been documented. Now measles is resurging, which no one in public health finds surprising. The warnings were there. The numbers were there. The response was not.

This is the pattern that sits at the center of most prevention failures. The problem is rarely that no one saw the danger. It is what happens next.

Why does this happen? Part of the answer is psychological. Human beings are not built to respond well to slow-building threats. We respond to the emergency more readily than to the conditions that produced it. By the time a threat feels urgent, the window for prevention has usually closed.

Another part of the answer is something harder to name. Prevention has a paradox at its core. When it works, nothing happens. The disease does not spread. The child does not get sick. The absence of catastrophe rarely commands attention. The systems that prevent are chronically undervalued, and the people who maintain them are perpetually underfunded. Measles makes this visible in its starkest form. The elimination itself made people forget why it mattered. Prevention can undermine itself by making the original threat feel remote.

A third part of the answer is structural. When prevention works, the people it protects rarely know they were protected. Its benefits are spread across millions of people, none of whom can point to what they were spared. There are costs for prevention. Someone has to fund the clinic, pass the rule, absorb the inconvenience, and take the political risk. Acting early means fighting a visible battle against invisible future harm. Waiting means the damage eventually shows up in a form everyone can see, and responding to it is easier to justify.

Evidence can be translated into solutions, and solutions can be implemented. School vaccination requirements work because they make the decision routine. A child cannot enroll without the shot. The exemption exists, but claiming it takes more effort than getting the vaccination. The default tilts toward protection. Scientific facts were converted into a binding enrollment rule. The implementation was the thousand small administrative decisions that made the rule actually govern behavior, including the forms, the deadlines, and the school nurse who checks the records. Neither step alone would have been sufficient. Together, they produced one of the most successful prevention systems in American public health.

Seat belt laws followed the same architecture. The translation turned decades of crash research into statutes requiring seat belts to be installed and worn. The implementation was harder and slower. It included primary enforcement laws, public education campaigns, sustained political attention, and eventually a cultural shift in which buckling up became the default rather than the exception. Neither the law on the page nor the behavior on the road was enough on its own. Prevention worked because both gaps closed.

The debate over social media and children shows the same forces at work. For a decade, parents, clinicians, and teachers sensed that something was changing in adolescent life. Researchers produced data. Public concern widened. The warnings were audible years before the response arrived. Only in the last year has the pace changed. Australia’s social media age restriction took effect in December 2025. School districts across the country are banning phones from classrooms. A Los Angeles jury recently found Meta and Google liable in a closely watched social media addiction case. At least twenty states have now enacted laws governing minors’ social media use.

History rarely shows that we knew nothing. More often, it shows that someone had seen the pattern, someone had raised the alarm, and someone had tried to reduce the delay between warning and response.

That failure to act in time is one of the central themes of my forthcoming book, The Preventioneers, which traces how prevention has succeeded, how it has been resisted, and how often it has been delayed.