Put on the spot, a lot of Americans might hesitate over the difference between Medicaid and Medicare. People who aren’t affected by one of these programs, which together enroll about 150 million people in the U.S., don’t generally have a need to be well versed in their intricacies, and the two programs sound quite similar. The names don’t really hint that Medicare is a federal program that covers older Americans and Americans with disabilities, and that Medicaid covers low-income people in the United States.

Most Americans, though, are not nominated to become secretary of the Department of Health and Human Services. Robert F. Kennedy Jr. is. And yet today, at his confirmation hearing before the Senate Finance Committee, he made clear that he also does not know very much about Medicare and Medicaid.

As HHS secretary, Kennedy would oversee a suite of government agencies, including the FDA, CDC, and National Institutes of Health, that are focused on improving American health. He also would oversee the Centers for Medicare and Medicaid Services, which, as the name implies, manages those two programs. HHS services, in other words, touch the lives of every American—and Medicaid and Medicare are, in particular, two of the most common ways for people to directly benefit from the government’s services.

During the three-and-a-half-hour hearing, in which the Senate committee pressed Kennedy on a range of issues—his anti-vaccine views, endorsements of conspiracy theories, stance on abortion, potential financial conflicts—senators grilled Kennedy on various aspects of the two government programs. In his new role, Kennedy could be charged with overseeing substantial changes to one of them. Donald Trump has pledged to preserve Medicare. He has made no such promise about Medicaid, which health-policy experts anticipate may be targeted for spending cuts. (On Tuesday, Medicaid reimbursement portals abruptly stopped working after the Trump administration ordered a freeze on federal grants and loans; states have since regained access to the portals.) Some Republicans have argued that an increased focus on public-health insurance in the U.S. won’t make Americans healthier, and Kennedy appeared to echo that viewpoint today when he criticized Medicaid, saying “our people are getting sicker every single year,” and lamented the program’s expansion to people with higher incomes. “The poorest Americans are now being robbed,” he said.

But Kennedy also seemed to mix up the two programs when he described them. Part of the issue with Medicaid, he said, is that “the premiums are too high, the deductibles are too high.” The majority of people enrolled in Medicaid don’t pay premiums or deductibles; federal law actually prohibits premiums for the program’s lowest-income enrollees. (He did seem better versed in Medicare Advantage, a program that provides private insurance coverage for older Americans and that he himself is enrolled in.)

To be fair, Kennedy was in a high-pressure situation. But being HHS secretary is a high-pressure job. Kennedy had time to prepare in advance of today’s hearing. If confirmed, he won’t need to master every minute detail of Medicare and Medicaid, but he will need to be able to navigate both programs—their differences, their weaknesses, and how they might evolve. People who are eligible for both programs, for instance, have created sticking points in the health-care system, in part because coordinating coverage between the two is difficult and can complicate care. When pressed by Senator Bill Cassidy of Louisiana on how to deal with that issue, Kennedy suggested that the programs should be “consolidated” and “integrated”—but when asked how that might happen, said, “I’m not exactly sure.”

Kennedy struggled with other policy specifics, too. One of his goals, Kennedy said, is to fulfill Trump’s directive to improve the quality of care and lower the price of care for all Americans. But he was vague on any plans to reform Medicaid, explaining that he’d “increase transparency” and “increase accountability.” When pushed by Cassidy to clarify, Kennedy said, “Well, I don’t have a broad proposal for dismantling the program.”

Nor did Kennedy have a clear sense of how he would approach one of the more contentious and legally sensitive health questions of the past few years: whether women whose lives are threatened by pregnancy should be able to receive emergency abortions under EMTALA, the law that requires emergency rooms that receive Medicare funding to provide care to anyone in a life-threatening situation. The Biden administration argued that this federal law supersedes state abortion bans, and in 2024, after the Supreme Court demurred on the issue, the administration made clear to doctors, in a letter co-authored by Health and Human Services Secretary Xavier Becerra, that abortions could qualify as emergency treatment. Kennedy admitted this morning that he didn’t know the scope of the authority he’d have to enforce the law in his new job.

Jacinda Abdul-Mutakabbir, a clinical pharmacist at UC San Diego, told me that Kennedy's apparent failure to understand the intricacies of the two programs wasn’t just a harmless fumble. If the health secretary is not well versed in the programs he’s tasked to run, he might not appreciate the impacts of his decisions. Should health coverage for some of the most vulnerable Americans be altered—perhaps even taken away—then health disparities in this country would likely widen. And if any part of his agenda does include increasing transparency, as Kennedy described in today’s hearing, expertise will have to be a prerequisite. “You can’t increase transparency on something you don’t have clarity on,” Abdul-Mutakabbir told me. (Kennedy’s press team did not immediately return a request for comment on his performance at today’s hearing.)

During the hearing, Kennedy’s more radical views on vaccines and infectious disease did come up. He copped to describing Lyme disease as “highly likely a militarily engineered bioweapon.” (The bacterium, which has been around for at least tens of thousands of years, is not.) He stood by his assertion that the measles vaccine killed two children in Samoa in 2018. (The vaccine did not; those children died following the administration of an improperly mixed vaccine by two nurses who were ultimately sentenced to five years in prison for the act.) He said that young children are at “basically … zero risk” from COVID-19. (Young children are at risk, especially babies under six months of age, who have similar hospitalization rates from the disease as adults 65 to 74 years old.) Kennedy’s falsehoods about infection and immunity were already well known, though. What the country learned today was that he may lack basic competency in some of the most wide-reaching aspects of his future job—and didn’t take the time to prepare answers for Congress, which he’ll ultimately have to answer to.

Shortly after birth, newborns in the United States receive a few quick procedures: an Apgar test to check their vitals, a heel stick to probe for genetic disorders and various other conditions, and in most cases, a hepatitis B vaccine. Without that last one, kids are at risk of getting a brutal, and sometimes deadly, liver condition. Senator Bill Cassidy of Louisiana happens to know quite a lot about that. Before entering Congress in 2009, he was a physician who has said he was so affected by an 18-year-old patient with liver failure from the virus that he spearheaded a campaign that vaccinated 36,000 kids against hepatitis B.

Cassidy, a Republican, will now play a major role in determining the fate of Robert F. Kennedy Jr., Donald Trump’s pick for health secretary, whose confirmation hearings begin today on Capitol Hill. Kennedy has said that the hepatitis B vaccine is given to children only because the pharmaceutical company Merck colluded with the government to get the shot recommended for kids, after the drug’s target market (“prositutes and male homosexuals,” by Kennedy’s telling) weren’t interested in the shot. Kennedy will testify in front of the Senate Finance Committee, where Cassidy and 26 other senators will get the chance to grill him about his views. Though it might seem impossible for an anti-vaccine conspiracist to gain the support of a doctor who still touts the work he did vaccinating children, Cassidy has not indicated how he will vote. Similar to the Democratic senators who have come out forcefully against Kennedy, Cassidy, in an interview with Fox News earlier this month, said that RFK Jr. is “wrong” about vaccines. But he also said that he did agree with him on some things. (Cassidy’s office declined my request to interview the senator.)

That Kennedy even has a chance of winning confirmation is stunning in its own right. A longtime anti-vaxxer with a propensity for far-fetched conspiracy theories, RFK Jr. has insinuated that an attempt to assassinate members of Congress via anthrax-laced mail in 2001 may have been a “false flag” attack orchestrated by “someone in our government” to gin up interest in the government preparing for potential biological weapon threats. He has claimed that COVID was “targeted to attack Caucasians and Black people,” and that 5G is being used to “harvest our data and control our behavior.” He has suggested that the use of antidepressants might be linked to mass shootings. Each one of these theories is demonstrably false. The Republican Party has often found itself at war with mainstream science in recent years, but confirming RFK Jr. would be a remarkable anti-science advance. If Republican senators are willing to do so, is there any scientific belief they would place above the wishes of Donald Trump?

A number of Republicans have already signaled where they stand. In the lead-up to the confirmation hearings, some GOP senators have sought to sanewash RFK Jr., implying that his views really aren’t that extreme. They have reason to like some of what he’s selling: After the pandemic, many Republicans have grown so skeptical of the public-health establishment that Kennedy’s desire to blow it up can seem enticing. And parts of RFK Jr.’s “Make America Healthy Again” agenda do in fact adhere to sound scientific evidence. His views on how to tackle America’s epidemic of diet-related diseases are fairly well reasoned: Cassidy has said that he agrees with RFK Jr.’s desire to take action against ultra-processed foods. Kennedy appears to have won over the two other Republican doctors on the committee, Senators Roger Marshall of Kansas and John Barrasso of Wyoming. Marshall has been so enthusiastic about Kennedy’s focus on diet-related diseases that he has created a “Make America Healthy Again” caucus in the Senate. Although Barrasso hasn’t formally made an endorsement, he has said that Kennedy would provide a “fresh set of eyes” at the Food and Drug Administration. (Spokespeople for Barrasso and Marshall did not respond to requests for comment.)

[Read: Everyone agrees Americans aren’t healthy]

Meanwhile, Kennedy appears to have gone to great lengths to sand down his extremist views and present himself as a more palatable candidate. “He told me he is not anti-vaccine. He is pro–vaccine safety, which strikes me as a rational position to take,” Senator John Cornyn of Texas told Politico. He has also done more to drum up unnecessary fear about COVID shots than perhaps anyone else in the country. Nearly four years ago, Kennedy petitioned the federal government to revoke authorization for the shots, because “the current risks of serious adverse events or deaths outweigh the benefits.” (COVID shots are highly safe and effective. A spokesperson for Kennedy did not respond to a request for comment.)

Especially on the right, Kennedy’s conspiracy theories have not consumed his candidacy: With concerns about conflicts of interest, his support of abortion, and generally strange behavior (such as dumping a dead bear in Central Park), there is much to debate. If Republican senators skirt around his falsehoods during today’s confirmation hearings, it will be evidence of their prevailing capitulation to Trump. And it also may be a function of Kennedy’s rhetorical sleights. As Benjamin Mazer recently wrote in The Atlantic, Kennedy is not simply a conspiracy theorist, but an excellent one. He’s capable of rattling off vaccine studies with the fluency of a virologist, which boosts his credibility, even though he’s freely misrepresenting reality.

[Read: RFK Jr. is an excellent conspiracy theorist]

During his recent appearance on Joe Rogan’s podcast, Kennedy claimed that thimerosal, a preservative containing mercury used to protect vaccines from contamination, was found to cause “severe inflammation” in the brain of monkeys. Kennedy was able to quickly name the lead author and introduce the methods as if he has read the study hundreds of times. But Kennedy’s central claim—that the brains of monkeys given thimerosal were severely inflamed—is a “total misrepresentation” of the study, its lead author, Thomas M. Burbacher, told me. The problem is that Kennedy gets away with these claims because very few listeners are going to log onto PubMed to track down the study Kennedy is referencing, let alone read through the entire thing.

In theory, senators should be equipped to push back on his schtick. RFK Jr.’s positions are hardly a mystery, and senators have advisers to help them prepare for such hearings. Regardless of Kennedy’s pseudoscientific beliefs, some Republicans may support him simply because they are wary of bucking their president. Before Kennedy even makes it to a full vote from the Senate, he has to receive approval from the Senate Finance Committee: Given the tight margins in the committee, Kennedy can’t afford to lose a single vote from Republicans sitting on that panel, assuming that no Democrats support his nomination. I reached out to the offices of seven Republican senators on the committee who haven’t already backed Kennedy for clarity on where they stand; none of them gave me a straight answer on how they’d vote.

In all likelihood, the first big decision in Kennedy’s nomination will fall to Cassidy. He has proved willing to oppose Trump before. Cassidy was one of seven Republicans who voted to convict Trump during his second impeachment proceedings. That led Louisiana’s Republican Party to formally censure him, and has drawn him a primary challenger for his 2026 reelection bid. Although Cassidy criticized Trump during the 2024 campaign, he now seems eager to support him. “Today, the American people start winning again,” Cassidy wrote in a statement on Inauguration Day.

Perhaps Cassidy will still dissect Kennedy’s views with the precision of a surgeon’s scalpel. He likes to dive deep into health-care minutiae any chance he gets. (I would know: He once pulled out his iPad and lectured me and other reporters about some arcane drug-pricing policy.) But if today’s meeting is full of softball questions, it could put RFK Jr. on his way to confirmation. That would send a message that, science-wise, the Senate is willing to cede all ground. Trump could pursue the most radical parts of the Project 2025 agenda, such as splitting up the CDC, or Kennedy could launch a full-blown assault on vaccines—and the Senate would be in a much less powerful position to stop it even if it wanted to. If senators hand the keys of a nearly $2 trillion health-care agency to a known conspiracy theorist, anything goes.

Becoming a public-health expert means learning how to envision humanity’s worst-case scenarios for infectious disease. For decades, though, no one in the U.S. has had to consider the full danger of some of history’s most devastating pathogens. Widespread vaccination has eliminated several diseases—among them, measles, polio, and rubella—from the country, and kept more than a dozen others under control. But in the past few years, as childhood-vaccination rates have dipped nationwide, some of infectious disease’s ugliest hypotheticals have started to seem once again plausible.

The new Trump administration has only made the outlook more tenuous. Should Robert F. Kennedy Jr., one of the nation’s most prominent anti-vaccine activists, be confirmed as the next secretary of Health and Human Services, for instance, his actions could make a future in which diseases resurge in America that much more likely. His new position would grant him substantial power over the FDA and the CDC, and he is reportedly weighing plans—including one to axe a key vaccine advisory committee—that could prompt health-care providers to offer fewer shots to kids, and inspire states to repeal mandates for immunizations in schools. (Kennedy’s press team did not respond to a request for comment.)

Kennedy’s goal, as he has said, is to offer people more choice, and many Americans likely would still enthusiastically seek out vaccines. Most Americans support childhood vaccination and vaccine requirements for schools; a KFF poll released today found, though, that even in the past year the proportion of parents who say they skipped or delayed shots for their children has risen, to one in six. The more individuals who choose to eschew vaccination, the closer those decisions would bring society’s collective defenses to cracking. The most visceral effects might not be obvious right away. For some viruses and bacteria to break through, the country’s immunization rates may need to slip quite a bit. But for others, the gap between no outbreak and outbreak is uncomfortably small. The dozen experts I spoke with for this story were confident in their pessimism about how rapidly epidemics might begin.

[Read: How America’s fire wall against disease starts to fail]

Paul Offit, a pediatrician at Children’s Hospital of Philadelphia and co-inventor of one of the two rotavirus vaccines available in the U.S., needs only to look at his own family to see the potential consequences. His parents were born into the era of the deadly airway disease diphtheria; he himself had measles, mumps, rubella, and chickenpox, and risked contracting polio. Vaccination meant that his own kids didn’t have to deal with any of these diseases. But were immunization rates to fall too far, his children’s children very well could. Unlike past outbreaks, those future epidemics would sweep across a country that, having been free of these diseases for so long, is no longer equipped to fight them.

“Yeah,” Offit said when I asked him to paint a portrait of a less vaccinated United States. “Let’s go into the abyss.”

Should vaccination rates drop across the board, one of the first diseases to be resurrected would almost certainly be measles. Experts widely regard the viral illness, which spreads through the air, as the most infectious known pathogen. Before the measles vaccine became available in 1963, the virus struck an estimated 3 million to 4 million Americans each year, about 1,000 of whom would suffer serious swelling of the brain and roughly 400 to 500 of whom would die. Many survivors had permanent brain damage. Measles can also suppress the immune system for years, leaving people susceptible to other infections.

Vaccination was key to ridding the U.S. of measles, declared eliminated here in 2000. And very high rates of immunity—about 95 percent vaccine coverage, experts estimate—are necessary to keep the virus out. “Just a slight dip in that is enough to start spurring outbreaks,” Boghuma Kabisen Titanji, an infectious-disease physician at Emory University, told me. Which has been exactly the case. Measles outbreaks do still occur in American communities where vaccination rates are particularly low, and as more kids have missed their MMR shots in recent years, the virus has found those openings. The 16 measles outbreaks documented in the U.S. in 2024 made last year one of the country’s worst for measles since the turn of the millennium.

But for all measles’ speed, “I would place a bet on whooping cough being first,” Samuel Scarpino, an infectious-disease modeler at Northeastern University, told me. The bacterial disease can trigger months of coughing fits violent enough to fracture ribs. Its severest consequences include pneumonia, convulsions, and brain damage. Although slower to transmit than measles, it has never been eliminated from the U.S., so it’s poised for rampant spread. Chickenpox poses a similar problem. Although corralled by an effective vaccine in the 1990s, the highly contagious virus still percolates at low levels through the country. Plenty of today’s parents might still remember the itchy blisters it causes as a rite of passage, but the disease’s rarer complications can be as serious as sepsis, uncontrolled bleeding, and bacterial infections known as “flesh-eating disease.” And the disease is much more serious in older adults.

Those are only some of the diseases the U.S. could have to deal with. Kids who get all of the vaccines routinely recommended in childhood are protected against 16 diseases—each of which would have some probability of making a substantial comeback, should uptake keep faltering. Perhaps rubella would return, infecting pregnant women, whose children could be born blind or with heart defects. Maybe meningococcal disease, pneumococcal disease, or Haemophilus influenzae disease, each caused by bacteria commonly found in the airway, would skyrocket, and with them rates of meningitis and pneumonia. The typical ailments of childhood—day-care colds, strep throat, winter norovirus waves—would be joined by less familiar and often far more terrifying problems: the painful, swollen necks of mumps; the parching diarrhea of rotavirus; the convulsions of tetanus. For far too many of these illnesses, “the only protection we have,” Stanley Plotkin, a vaccine expert and one of the developers of the rubella vaccine, told me, “is a vaccine.”

Exactly how and when outbreaks of these various diseases could play out—if they do at all—is impossible to predict. Vaccination rates likely wouldn’t fall uniformly across geographies and demographics. They also wouldn’t decrease linearly, or even quickly. People might more readily refuse vaccines that were developed more recently and have been politicized (think HPV or COVID shots). And existing immunity could, for a time, still buffer against an infectious deluge, especially from pathogens that remain quite rare globally. Polio, for instance, would be harder than measles to reestablish in the United States: It was declared eliminated from the Americas in the 1990s, and remains endemic to only two countries. This could lead to a false impression that declining vaccination rates have little impact.

A drop in vaccination rates, after all, doesn’t guarantee an outbreak—a pathogen must first find a vulnerable population. This type of chance meeting could take years. Then again, infiltrations might not take long in a world interconnected by travel. The population of this country is also more susceptible to disease than it has been in past decades. Americans are, on average, older; obesity rates are at a historical high. The advent of organ transplants and cancer treatments has meant that a substantial sector of the population is immunocompromised; many other Americans are chronically ill. Some of these individuals don’t mount protective responses to vaccinations at all, which leaves them reliant on immunity in others to keep dangerous diseases at bay.

If various viruses and bacteria began to recirculate in earnest, the chance of falling ill would increase even for healthy, vaccinated adults. Vaccines don’t offer comprehensive or permanent protection, and the more pathogen around, the greater its chance of breaking through any one person’s defenses. Immunity against mumps and whooping cough is incomplete, and known to wane in the years after vaccination. And although immunity generated by the measles vaccine is generally thought to be quite durable, experts can’t say for certain how durable, Bill Hanage, an infectious-disease epidemiologist at Harvard’s School of Public Health, told me: The only true measure would be to watch the virus tear through a population that hasn’t dealt with it in decades.

Perhaps the most unsettling feature of a less vaccinated future, though, is how unprepared the U.S. is to confront a resurgence of pathogens. Most health-care providers in the country no longer have the practical knowledge to diagnose and treat diseases such as measles and polio, Kathryn Edwards, a pediatrician at Vanderbilt University, told me: They haven’t needed it. Many pediatricians have never even seen chickenpox outside of a textbook.

To catch up, health-care providers would need to familiarize themselves with signs and symptoms they may have seen only in old textbooks or in photographs. Hospitals would need to use diagnostic tests that haven’t been routine in years. Some of those tools might be woefully out of date, because pathogens have evolved; antibiotic resistance could also make certain bacterial infections more difficult to expunge than in decades prior. And some protocols may feel counterintuitive, Offit said: The ultra-contagiousness of measles could warrant kids with milder cases being kept out of health-care settings, and kids with Haemophilus influenzae might need to be transported to the hospital without an ambulance, to minimize the chances that the stress and cacophony would trigger a potentially lethal spasm.

[Read: Here’s how we know RFK Jr. is wrong about vaccines]

The learning curve would be steep, Titanji said, stymieing care for the sick. The pediatric workforce, already shrinking, might struggle to meet the onslaught, leaving kids—the most likely victims of future outbreaks—particularly susceptible, Sallie Permar, the chief pediatrician at NewYork–Presbyterian/Weill Cornell Medical Center, told me. If already overstretched health-care workers were further burdened, they’d be more likely to miss infections early on, making those cases more difficult to treat. And if epidemiologists had to keep tabs on more pathogens, they’d have less capacity to track any single infectious disease, making it easier for one to silently spread.

The larger outbreaks grow, the more difficult they are to contain. Eventually, measles could once again become endemic in the U.S. Polio could soon follow suit, imperiling the fight to eradicate the disease globally, Virginia Pitzer, an infectious-disease epidemiologist at Yale, told me. In a dire scenario—the deepest depths of the abyss—average lifespans in the U.S. could decline, as older people more often fall sick, and more children under 5 die. Rebottling many of these diseases would be a monumental task. Measles was brought to heel in the U.S. only by decades of near-comprehensive vaccination; re-eliminating it from the country would require the same. But the job this time would be different, and arguably harder—not merely coaxing people into accepting a new vaccine, but persuading them to take one that they’ve opted out of.

That future is by no means guaranteed—especially if Americans recall what is at stake. Many people in this country are too young to remember the cost these diseases exacted. But Edwards, who has been a pediatrician for 50 years, is not. As a young girl, she watched a childhood acquaintance be disabled by polio. She still vividly recalls patients she lost to meningitis decades ago. The later stages of her career have involved fewer spinal taps, fewer amputations. Because of vaccines, the job of caring for children, nowadays, simply involves far less death.

Robert F. Kennedy Jr., President Donald Trump’s nominee for secretary of Health and Human Services, is a longtime conspiracy theorist and anti-vaccine activist. He thinks Anthony Fauci and Bill Gates are leaders of a “vaccine cartel” that intentionally prolonged or even started the coronavirus pandemic in order to promote “mischievous inoculations.” Kennedy also blames immunizations for autism and obesity (among other chronic diseases) in children. In the meantime, he isn’t really sure whether HIV causes AIDS, or whether vaccine-preventable diseases such as measles are actually dangerous.

As a doctor, I have spent years following—and fighting—anti-vaccine falsehoods. Along the way, I’ve learned an important lesson: Despite RFK Jr.’s fringe beliefs, he often seems to make sense. Kennedy’s defenders celebrate his fondness for, and facility with, evidence. His real talent, though, is for the clever manipulation of facts. Kennedy is not just a conspiracy theorist; he’s a very good conspiracy theorist. When his confirmation hearing starts on Wednesday, we can expect that he will do what he’s always done, which is to apply a veneer of erudition to nonsense. He may even come off as almost … reasonable.

To witness how this works, read the letter he sent to the prime minister of Samoa on behalf of the anti-vaccine nonprofit Children’s Health Defense in November 2019, during that country’s deadly measles outbreak. Kennedy offers his condolences for the tragic deaths of “precious Samoan children,” and then suggests the need to study the outbreak carefully, so as to “thoroughly understand its etiology.” What might have caused thousands of Samoans to get sick? The letter poses two possibilities: “It is critical that the Samoan Health Ministry determine, scientifically, if the outbreak was caused by inadequate vaccine coverage or alternatively, by a defective vaccine.”

At first glance, and for nonexperts, this letter may appear well reasoned and well sourced. It weaves in historical elements and biomedical data, and includes a list of peer-reviewed references at the end. The letter’s main request—that Samoan officials do nothing more than perform genetic testing on the circulating virus—sounds prudent. Prior research has indicated that vaccinated individuals may shed the virus and infect others, the letter says. Wouldn’t it be good to know if that produced the outbreak?

[Read: We’re about to find out how much Americans like vaccines]

In reality, of course, the epidemic was caused not by the vaccines but by the lack of them. (A vaccine-administration accident the year before had produced a scare that led vaccination rates to decline dramatically.) Although the letter’s implication that vaccines were to blame seemed wrong on its face, only when I dived into the cited scientific articles could I see the problems with its details. Kennedy incorrectly claims that genetic sequencing of a large measles outbreak in California from about four years prior found that at least one-third of the cases were due to the vaccine. “Alarmed CDC officials documented this emerging phenomenon,” he wrote. The referenced articles show this to be a fundamental misrepresentation. Although they do describe how the vaccine may, in rare cases, produce a dangerous case of measles, they specifically note that there is no risk of its being transmitted to another person. The genetic testing that Kennedy referenced is used, in part, to distinguish among people who have experienced mild vaccine reactions such as rash and fever from those who have true measles infections. This is important during active epidemics when public-health officials are widely immunizing people, while at the same time trying to isolate infectious individuals. (Kennedy’s press team did not respond to emailed questions about his letter to Samoa, or about other issues with his credibility that are raised in this article.)

A complete refutation of the Samoa letter would run many pages. That may be the point. With his ample, erroneous allusions to scholarship and appeals to authority, Kennedy has perfected the art of the Gish Gallop: a debate strategy in which the speaker simply overwhelms the listener with information, not all of it true. Kennedy’s skill at flooding his audiences with specious claims that sound logical or highbrow was on full display during his 2023 interview with the podcaster Joe Rogan. Over the course of three hours, Kennedy regaled the host with stories about vaccine safety, Albert Camus, Wi-Fi radiation, and the sexual health of frogs, among other subjects. He offered up a bounty of scientific arguments: The words study and studies came up 70 times during the conversation. And, as he has done elsewhere, he encouraged the audience to fact-check everything he said. “Nobody should trust my word on this,” he declared. “You know, what I say is irrelevant. What is relevant is the science.”

[Read: The new Rasputins]

Most of Rogan’s listeners—like most U.S. senators—aren’t likely to have the scientific expertise to assess each of his claims, and certainly not in real time. I caught some errors in the Rogan interview only by virtue of my medical training. For example, Kennedy criticized the inclusion of the hepatitis B shot in the childhood vaccine schedule. The virus is primarily a problem for intravenous-drug users, prostitutes, and homosexuals, he suggested. “Why would you give it to a one-day-old baby, you know, or a three-hour-old baby, and then four more times when that baby is not going to be even subject to it for 16 years?” he asked Rogan. Kennedy’s story sounds informed: He is facile with epidemiology and vaccine regulations; he can describe historical machinations that supposedly took place between Merck and the CDC. But the truth is that most chronic hepatitis B infections are contracted during early childhood, or through mother-to-child transmission. That’s why the World Health Organization recommends immunizing babies, and it’s why nearly every country has chosen to do so.

Kennedy does, at times, say true things about vaccines. He was not wrong, for example, when he told the podcaster Lex Fridman that early batches of the polio vaccine were contaminated with a virus called SV40. But he magnifies and distorts such flaws to the point of absurdity. SV40-containing vaccines did not cause an “explosion” of cancers, as he has argued. Kennedy is also right to say the MMR vaccine doesn’t always provide lifelong immunity to the mumps virus. However, his more extreme assertions—that the shot is causing mumps outbreaks in the military or that the disease is harmless in children—are wrong. (Before vaccination, service members routinely suffered from infections, and kids were at a heightened risk of developing brain inflammation and hearing loss.) Kennedy relies on scraps of truth to construct an alternative reality in which vaccines don’t work, their harms outweigh their benefits, and the diseases themselves aren’t so bad.

At his confirmation hearing, senators will ask him to defend that dangerous, alternative reality. He is likely to do so with impressive-sounding falsehoods, delivered with aplomb. Heed his own advice. No one should trust his word on this.

Just outside New York City’s Central Park Zoo, not far from where Robert F. Kennedy Jr. once stealthily deposited a dead bear cub, stands a bronze statue to another animal: Balto, the husky that, 100 years ago this month, played a leading role in a daring and perilous rescue that captured the world’s attention.

Nome, a small town in the northwestern reaches of the Alaskan territories, had been hit with an outbreak of diphtheria, a highly contagious and cruel respiratory infection that can be particularly deadly to the young. As the children of Nome and surrounding communities fell ill, and some died, the town’s one doctor sent a desperate plea to state and national officials for a fresh supply of the antitoxin serum needed to treat the infected and stem a larger epidemic.

But Nome, with its subarctic climate, was icebound in winter and nearly unreachable. With little time to waste, locals organized a relay of dogsleds to transport the needed doses across 674 treacherous miles of Alaskan wilderness in temperatures as low as 50 degrees below zero. In all, 20 heroic men and 150 dogs braved the unsparing elements to deliver the lifesaving serum. Balto anchored the final lap.

The centennial of this heroic expedition is particularly timely, coming as the United States Senate considers President Donald Trump’s nomination of Kennedy, a serial purveyor of dangerous disinformation about vaccines, to lead the Department of Health and Human Services.

[Read: We’re about to find out how much Americans like vaccines]

It is not too obvious, in 2025, to state that vaccines work. In 1921, before the scientific breakthrough that led to the Tdap vaccine, approximately 200,000 Americans were infected with diphtheria, and 15,000 died. By the turn of the century, thanks to compulsory vaccination of schoolchildren, the number of cases dwindled to almost nothing. From 1996 to 2018, America experienced an average of fewer than one case a year. Polio, measles, and many other potentially deadly diseases also were virtually eradicated by vaccines.

Yet a rising anti-vax movement, fueled by click-hungry demagogues and a growing populist revolt against experts, institutions, and mandates, threatens to drag America backwards. The movement was turbocharged by political resistance to the COVID vaccines, whose development Trump helped speed and deservedly heralded. Near-universal vaccination rates among America’s schoolchildren are dropping. Even slight declines threaten the herd immunity that protects entire communities from the spread of disease. Predictably, potentially deadly childhood diseases are becoming more common again.

For two decades, RFK Jr. has stood at the forefront of this anti-vaccine movement. In books, speeches, and social-media posts, he has championed a widely discredited theory that certain vaccines promote autism and suggested that life under America’s COVID-vaccine mandates was worse than under Hitler’s fascist regime (he apologized for the latter remark).

In 2021, The New York Times recently reported, Kennedy’s Children Health Defense organization petitioned the FDA to withdraw its authorization of the COVID vaccines, which already had saved hundreds of thousands of people and would allow Americans to resume their normal lives. In the petition, Kennedy’s organization argued that the vaccines were not only harmful but unnecessary, and embraced disproven and dangerous theories about alternative treatments.

[Read: What going ‘wild on health’ looks like]

In 2022, the attorney Aaron Siri, a top Kennedy adviser, filed a petition asking the FDA to rescind its approval of the polio vaccine, which, since its inception in the 1950s, has been used by billions of people and has helped subdue that dreaded scourge. For a time, Siri reportedly helped Kennedy screen candidates for future HHS positions and was thought to be in line for one himself, but a transition spokesperson told The Wall Street Journal last week that he was no longer involved.

Kennedy presents the Senate with an interesting dilemma. He bears the name, if not the outlook or gravitas, of his famous father. His emphasis on healthy eating and physical fitness to combat obesity is as sensible now as it was when First Lady Michelle Obama championed those causes in the previous decade, to the scorn of many Republicans. His environmentalism is so pronounced that Trump has publicly assured the “drill, baby, drill” crowd that Kennedy won’t “touch the oil and gas.” His anti-corporate bent and deep suspicion of government bureaucracy appeal to populists on the left and right. And government bureaucracies, which are particularly prone to inertia and special-interest influence, should be challenged.

But their renewal must be guided by facts, not exotic, debunked claims. If confirmed, Kennedy will oversee the FDA, which approves vaccines. He will have authority over the National Institutes of Health, which funds and underwrites essential research that leads to vaccines and cures, and the CDC, which plays a central role in quelling public-health threats. It is an awesome responsibility and a crucial platform, dangerous in the hands of a charlatan who places conspiracy theories over science.

[Read: RFK Jr. is in the wrong agency]

Vaccines and medications should be rigorously tested and scrutinized for their efficacy and side effects, free of pressure and lobbying from the firms that develop them. The public needs and deserves that confidence. But those tests and standards should be based on proven science and not quackery.

Kennedy will face intense questioning about all of this, as well as his stability and judgment, at his confirmation hearing, which is slated for Wednesday. If he is confirmed, his promotion of junk science and vaccine hesitancy could prove as threatening to American public health as the barriers posed by an unforgiving, frozen Alaskan wilderness were to the desperate children and parents of Nome a century ago.

At the foot of Balto’s memorial in Central Park are three words: Endurance, Fidelity, Intelligence. Can enough United States senators overcome political pressure and demonstrate those same qualities in the coming days?

For more than 60 years, vaccination in the United States has been largely shaped by an obscure committee tasked with advising the federal government. In almost every case, the nation’s leaders have accepted in full the group’s advice on who should get vaccines and when. Experts I asked could recall only two exceptions. Following 9/11, the Bush administration expanded the group who’d be given smallpox vaccinations in preparation for the possibility of a bioterrorism attack, and at the height of the coronavirus pandemic, in 2021, the Biden administration added high-risk workers to the groups urged to receive a booster shot. Otherwise, what the Advisory Committee on Immunization Practices (ACIP) has recommended has effectively become the country’s unified vaccination policy.

This might soon change. Robert F. Kennedy Jr., one of the nation’s most prominent anti-vaccine activists and the likely next secretary of Health and Human Services, has said that he would not “take away” any vaccines. But Kennedy, if confirmed, would have the power to entirely remake ACIP, and he has made clear that he wants to reshape how America approaches immunity. Gregory Poland, the president of the Atria Academy of Science and Medicine and a former ACIP member, told me that if he were out to do just that, one of the first things he’d do is “get rid of or substantially change” the committee.

Over the years, the anti-vaccine movement has vehemently criticized ACIP’s recommendations and accused its members of conflicts of interest. NBC News has reported that, in a 2017 address, Kennedy himself said, “The people who are on ACIP are not public-health advocates … They work for the vaccine industry.” Kennedy has not publicly laid out explicit plans to reshuffle the makeup or charter of ACIP, and his press team did not return a request for comment. But should he repopulate ACIP with members whose views hew closer to his own, those alterations will be a bellwether for this country’s future preparedness—or lack thereof—against the world’s greatest infectious threats.

[Read: ‘Make America Healthy Again’ sounds good until you start asking questions]

Before ACIP existed, the task of urging the public to get vaccinated was largely left to professional organizations, such as the American Academy of Pediatrics, or ad hoc groups that evaluated one immunization at a time. By the 1960s, though, so many new vaccines had become available that the federal government saw the benefit of establishing a permanent advisory group. Today, the committee includes up to 19 voting members who are experts drawn from fields such as vaccinology, pediatrics, virology, and public health, serving four-year terms. The CDC solicits nominations for new members, but the HHS secretary, who oversees the CDC and numerous other health-related agencies, ultimately selects the committee; the secretary can also remove members at their discretion. The committee “is intended to be a scientific body, not a political body,” Grace Lee, who chaired ACIP through the end of 2023, told me. ACIP’s charter explicitly states that committee members cannot be employed by vaccine manufacturers, and must disclose real and perceived conflicts of interest.

HHS Secretaries typically do not meddle extensively with ACIP membership or its necessarily nerdy deliberations, Jason Schwartz, a vaccine-policy expert at Yale, told me. The committee’s job is to rigorously evaluate vaccine performance and safety, in public view, then use that information to help the CDC make recommendations for how those immunizations should be used. Functionally, that means meeting for hours at a time to pore over bar graphs and pie charts and debate the minutiae of immunization efficacy. Those decisions, though, have major implications for the country’s defense against disease. ACIP is the primary reason the United States has, since the 1990s, had an immunization schedule that physicians across the country treat as a playbook for maintaining the health of both adults and kids, and that states use to guide school vaccine mandates.

The committee’s decisions have, over the years, turned the tide against a slew of diseases. ACIP steered the U.S. toward giving a second dose of the MMR vaccine to children before elementary school, rather than delaying it until early adolescence, in order to optimally protect kids from a trifecta of debilitating viruses. (Measles was declared eliminated in the U.S. in 2000.) The committee spurred the CDC’s recommendation for a Tdap booster during the third trimester of pregnancy, which has guarded newborn babies against whooping cough. It pushed the country to switch to an inactivated polio vaccine at the turn of the millennium, helping to prevent the virus from reestablishing itself in the country.

[Read: We’re about to find out how much Americans like vaccines]

I reached out to both current ACIP members and the Department of Health and Human Services to ask about Kenndy’s pending influence over the committee. ACIP Chair Helen K. Talbot and other current ACIP members emphasized the group’s importance to keeping the U.S. vaccinated, but declined to comment about politically motivated changes to its membership. The Department of Health and Human Services did not return a request for comment.

Should ACIP end up stacked with experts whose views mirror Kennedy’s, “it’s hard not to imagine our vaccination schedules looking different over the next few years,” Schwartz told me. Altered recommendations might make health-care providers more willing to administer shots to children on a delayed schedule, or hesitate to offer certain shots to families at all. Changes to ACIP could also have consequences for vaccine availability. Pharmaceutical companies might be less motivated to manufacture new shots for diseases that jurisdictions or health-care providers are no longer as eager to vaccinate against. Children on Medicaid receive free vaccines based on an ACIP-generated list, and taking a particular shot off that roster might mean that those kids will no longer receive that immunization at all.

At one extreme, the new administration could, in theory, simply disband the committee altogether, Schwartz told me, and have the government unilaterally lay down the country’s vaccination policies. At another, the CDC director, who has never been beholden to the committee’s advice, could begin ignoring it more often. (Trump’s choice to lead the CDC, the physician and former Florida congressman Dave Weldon, has been a critic of the agency and its vaccine program.) Most likely, though, the nation’s new health leaders will choose to reshape the committee into one whose viewpoints would seem to legitimize their own. The effects of these choices might not be obvious at first, but a committee that has less academic expertise, spends less time digging into scientific data, and is less inclined to recommend any vaccines could, over time, erode America’s defenses—inviting more disease, and more death, all of it preventable.

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For a few years in the 2010s, America seemed to be falling out of love with soda. But some blend of price-conscious shopping, kooky social-media trends (milk and coke, anyone?), and perhaps a streak of fatalistic behavior on the part of Americans has made the beverage newly relevant.

Soda consumption declined consistently over the decade leading up to 2015, in part because of backlash from a health-conscious public and a series of soda-tax battles; some soda drinking was also displaced by the likes of energy drinks, coffee, and bottled water. However, in 2017, the CDC announced that rates of sugary-beverage consumption had plateaued—at a rate far above the government-recommended limit. Now soda sales are ticking back up modestly: Coca-Cola and Dr Pepper both saw soda-case sales rise in the past year, and total sales volumes for soft drinks have risen, according to the investment-bank advisory firm Evercore ISI; last year, Coca-Cola was among the fastest-growing brands for women, Morning Consult found. Soda is having a cultural moment too: Addison Rae’s “Diet Pepsi” was a, if not the, song of the summer. And the U.S. president-elect is famously a fan of Diet Coke, reportedly drinking a dozen a day during his first term.

Compared with 20 years ago, Americans are drinking far fewer sugar-sweetened beverages, particularly soda—but compared with a decade ago, they are drinking almost as much, Dariush Mozaffarian, a physician and a nutrition expert at Tufts, told me. Researchers have suggested that there are links between drinking large amounts of sugary drinks and a range of negative health outcomes, but the people most open to changing their soda habits may have already changed them, Mozaffarian noted. In order for cultural norms around soda to shift, drinking it needs to become uncool, he argued. That’s not an impossible goal, but it can be achieved only through a combination of sustained policy efforts, strong messaging from public-health officials, and perhaps even a bit of help from celebrities.

Public-health messaging alone can’t get people to change their behavior. Soda brands have been “a part of our cultural life for decades,” my colleague Nicholas Florko, who covers health policy, told me. “And so there is going to be some reluctance if you tell people” to ease up on “this thing that your parents, your grandparents, your great-grandparents, have been drinking forever.” Part of the draw of soda is that it’s generally quite cheap. To undercut that appeal, activists and politicians have pushed to implement taxes on sugary drinks; in many cases, they have received major pushback from industry and business groups. Researchers have found that, in places where sugary-drink taxes managed to pass, they do help: One study last year found that sales of sugary drinks went down by a third in American cities with soda taxes, and there’s no evidence that people traveled beyond the area looking for cheaper drinks. But these taxes require political will—and pushing for people’s groceries to cost more is not always an appealing prospect for politicians, Nicholas pointed out, especially in our current moment, when Americans are still recovering from the effects of high inflation.

Soda taxes are controversial, but a soda tax isn’t just about cost: Part of the reason such policies work, says Justin White, a health-policy expert at Boston University, is that they can make sugary drinks seem less socially acceptable. “Policies affect the norms, and norms feed back into people’s choices,” he told me. Now new soda norms are emerging, including a crop of sodas that claim to be gut-healthy (although, Mozaffarian said, more research needs to be done to confirm such claims).

Soda feels like an intrinsic part of American life. But generations of canny advertising and celebrity endorsements, Mozaffarian noted, are responsible for embedding soda in so many parts of America—think of its placement in ballparks and other social spaces—and in the day-to-day rhythms of offices and schools. Curbing soda consumption would require a similarly intentional shift.

Related:

Being alive is bad for your health. Public health can’t stop making the same nutrition mistake.

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Dispatches

The Books Briefing: Two novels take different approaches to resurrecting the dead, Maya Chung writes. Atlantic Intelligence: TikTok is set to be banned in the U.S., following a decision by the Supreme Court. But the legacy of its algorithm will live on, Damon Beres writes.

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‘I Won’t Touch Instagram’

By Kaitlyn Tiffany

If TikTok does indeed get banned or directly shut off by its parent company, it would be a seismic event in internet history. At least a third of American adults use the app, as do a majority of American teens, according to Pew Research Center data. These users have spent the past few days coming to terms with the app’s possible demise—and lashing out however they could think to.

Read the full article.

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Stephanie Bai contributed to this newsletter.

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Over the past several months, bird-flu numbers have been steadily ticking up, especially among farmworkers who interact closely with cows. I spoke with my colleague Katherine J. Wu, who reports on science, about her level of concern right now, and the government’s response to the spread of the virus so far.

Lora Kelley: We last spoke in April, after a dairy worker became infected with bird flu. At the time, you described your level of concern about bird flu as “medium.” How would you describe your level of worry now?

Katherine J. Wu: At this point, I would upgrade it to “medium-plus.” I don’t think I will upgrade to “high” unless we start to see strong evidence of human-to-human transmission. I am not ruling out that possibility, but we aren’t there yet.

The situation has gotten quite a bit worse since last spring. We are seeing consistent infection of dairy workers, meaning an especially vulnerable population is exposed in their work environment. Each time the virus infects a new person, it’s an opportunity for it to evolve into something that could eventually become a pathogen that moves easily from person to person.

Lora: What could public-health officials have done differently in recent months to contain the outbreak?

Katherine: Part of the reason I feel concerned is the government’s lackluster response. The movement of the virus into cows was a huge red flag. Cows have never been a known source of this flu, so that was a complete surprise. That should have been a moment when officials said: We really need to contain this before it gets out of control. If some of the first afflicted herds had been kept from moving around, or even culled, it’s possible that the virus might have been contained before dairy workers got sick.

The USDA has ramped up its testing of milk, and the CDC is still working hard to do outreach to farmworkers, who are the population most at risk here. But there could still be more testing at the individual level—individual animals, individual people. There could be more frequent, aggressive sampling of where the virus is in the environment, as well as on farms.

Representatives at USDA and CDC have denied that their response has been inadequate—though independent experts I have spoken with dispute that. To be clear, officials can’t fully predict the future and stop an outbreak the second it starts to get bad, and critics aren’t demanding that. But right now, it’s still a very reactive approach: We see that the virus has been here; I guess we can keep checking if it’s there. But a more proactive approach with testing and better communication with the public would really help.

Lora: How has the government’s response to bird flu compared with its response to COVID?

Katherine: There’s no doubt that having COVID in the rearview affected the government’s response. I think they didn’t want to overreact and cause widespread panic when there wasn’t a need. That’s fair, but there’s a middle ground that I think they missed.

The response to COVID was by definition going to be haphazard, because we didn’t have a preexisting arsenal of tests, vaccines, and antivirals. We hadn’t dealt with a coronavirus like that in recent memory. Here, though, there is a slate of tools available. We’ve dealt with big flu outbreaks. We know what flu can do. We know that flu, in general, can move from animals into humans. We’ve seen this particular virus actually move into people in different contexts across the world.

Lora: Have we missed the opportunity to mitigate the spread of bird flu?

Katherine: Because there has not yet been evidence of sustained human-to-human transmission, there is still time to intervene. Did officials miss some opportunities to intervene more and earlier? Yes. But that doesn’t mean that from here the attitude should be I guess we should just let this roll.

Lora: We may have RFK Jr., a vaccine skeptic, leading the Department of Health and Human Services soon. How might his leadership affect the bird-flu response?

Katherine: I don’t think there is a need to roll out bird-flu vaccines to the general public yet. But I think there are likely to be major changes to public-health policy in this country. RFK Jr. has specifically said that the National Institutes of Health will be taking a break from focusing on infectious disease for the next few years, and that doesn’t bode terribly well. Infectious diseases are not going to take a break from us.

Lora: Are there lessons from the COVID era that the public should better absorb in order to deal with illness more broadly?

Katherine: To be fair, it’s hard to avoid getting sick in general, especially at this time of year. During the worst of the pandemic, when people were still masking more consistently and not going into public places, we did get sick a lot less often because we were avoiding each other.

That said, I think people did forget very, very quickly that the things that worked against COVID work well against a lot of other diseases, especially other respiratory viruses. I am not saying that we all need to go back to masking 24/7 and never going to school or work in person. But maybe don’t go to work when you’re sick—a practice that all employers should enable. Maybe don't send your child to day care sick. Maybe don’t sneeze into your hand and then rub your hand all over the subway railing. Wash your hands a lot.

Unfortunately, there is this tendency for a really binary response of doing everything or nothing. Right now, people seem to be leaning toward doing nothing, because they are fatigued from what they felt like was an era of doing everything. But there’s a middle ground here too.

Related:

Bird flu is a national embarrassment. America’s infectious-disease barometer is off. (From April)

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Juli Gittinger keeps a bag packed with iodine pills and a machete. “It’s good for getting through brush,” she explained to me recently. Gittinger’s mind churns with images of a future in which she might have to flee her home with just a backpack, bushwhacking her way through rural Georgia to safety. She has enough water in her house to last 30 days, and enough food to last 100 days.

Gittinger, a religious-studies professor at Georgia College, is a prepper, but unlike the stereotype that term commonly conjures—a bunker-bound, right-wing conspiracist—Gittinger is liberal. She began prepping after Donald Trump was elected in 2016. Among her prepping supplies are Plan B emergency contraceptive pills that she’s bought ahead of Trump’s second inauguration, in case his administration introduces new restrictions on reproductive health care.

Gittinger is representative of a small number of preppers who oppose Trump and who are gearing up for whatever disasters the next four years might bring. Across Reddit boards and Facebook groups, they are stocking up on and freeze-drying food—and say that others should be too.

[Read: Why liberals struggle to cope with epochal change]

Precise numbers on prepping are hard to come by, but the United States has likely millions of preppers of all political persuasions, says Michael Mills, a senior lecturer at Anglia Ruskin University, in the United Kingdom. Liberals make up a small percentage—about 15 percent, according to Mills. Like their conservative counterparts, liberal preppers are worried about the stability of the economy and the power grid, but unlike the conservatives, they also worry about climate-change-induced disasters and the potential that Trump will weaken America’s security through foreign-policy snafus. Mills is skeptical that the number of liberal preppers has dramatically increased, but the moderators of several liberal-prepping forums told me they’ve seen a spike in interest and activity since Trump’s reelection, in November. Several preppers I interviewed mentioned getting current on their vaccines, in case the new administration alters the rules for vaccine insurance coverage, or updating their passports, in case they feel they have to leave the country.

In addition to being a prepper herself, Gittinger has studied prepper groups and written about them in an academic book, American Apocalyptic. Starting in 2018, Gittinger surveyed several hundred liberal preppers (and a few conservatives) on Facebook. When she asked what got them into prepping, 31 of the 300-some respondents mentioned the election of Trump, and 35 mentioned “political anxieties.” Among the calamities they feared would strike were both the politically driven—economic and societal collapse, an attack from a foreign power—and the completely random: a pandemic, a natural disaster. “The country is so divided that anything could ignite riots like we haven’t seen before,” one respondent told her.

Lots of Americans are doing some version of prepping for Trump’s second term, even if they don’t call it that. Some providers of Plan B and abortion pills say they noticed an increase in orders immediately after the election. The election prompted many to rush to buy electronics, cars, and other goods ahead of Trump’s promised tariffs. Spending on vehicles, auto parts, and appliances rose in November, The Washington Post reported. Along with stocking up on food and water in anticipation of tariffs, Gittinger recently bought a new phone, and Zoe Higgins, another liberal prepper, bought a new car.

Genevra Hsu, a moderator of the Leftist Preppers subreddit, grew up learning survivalist techniques from her father, but she began prepping in earnest around 2013, when she moved to a rural area of Virginia. Some of her friends got into gardening, and she would give them tips. She now has six months of meals on hand—she does her own pressure-canning, dehydrating, and freezing. She’s at high risk of complications from COVID, so when the pandemic started, the stores provided an “animal comfort that comes from knowing there’s enough on the shelf that I don’t have to go anywhere,” she told me. Recently, she has started dehydrating and freezing powdered eggs in case of a bird-flu pandemic. On the subreddit, preppers discuss stocking up on toothpaste with fluoride, which Trump’s chosen health secretary, Robert F. Kennedy Jr., opposes adding to tap water. They’re buying up birth control and medical textbooks for treating vaccine-preventable diseases.

[Read: What going ‘wild on health’ looks like]

The line between prepping and emergency readiness is hazy. Indeed, some of the liberal preppers I interviewed seem more worried about act-of-God disasters such as hurricanes than a Handmaid’s Tale–type dystopia. KC Davis, the author of How to Keep House While Drowning, moved to Houston after 2017’s Hurricane Harvey and became concerned about flooding and losses of power. Now she keeps canned water, headlamps, thermal blankets, life jackets, rechargeable lanterns, and 30 days of emergency food on metal racks in her garage. She also has a generator, which fired up while we were talking.

In New Orleans, Higgins has a month’s worth of freeze-dried spaghetti, beef stroganoff, chicken alfredo, and other meals. She’s procured flashlights, headlamps, waterproof matches, fire starters, water-purification tablets, camping stoves, and propane tanks, along with something she calls a “bug-out binder” containing 400 pages of emergency checklists and instructions. Some preppers admit that the gear they’ve accumulated is less a preparation for a specific, Trump-related emergency and more a consequence of prepping gradually becoming a hobby, with ever more complicated gadgets for ever more outlandish scenarios. Among Gittinger’s prep is a Faraday bag—a backpack that blocks electromagnetic signals, in which Gittinger keeps a spare phone and a computer—to be used in case of an extreme solar flare.

Over and over, liberal preppers told me that they differ from their conservative counterparts because they are less conspiracy-minded and more concerned with helping their community rather than only their immediate family. (Gittinger wouldn’t need Plan B herself, but she bought it for other young women who might.) But like their right-wing counterparts, liberal preppers do tend to own guns, according to Gittinger: 121 of the 198 people who answered her survey question about weapons said they owned a firearm. Whom, exactly, they would use them against is less clear. “I think a lot of that is just out of a response to general uncertainty,” Hsu told me.

Another major commonality between liberal and conservative preppers is a distrust of the government, a feeling that institutions won’t help you if the worst comes to pass. For liberal preppers, this feeling has grown only more pronounced since the first Trump presidency. The rise of Trump, the fall of Roe v. Wade, and Republican victories in the states have given liberals the sense that they are on the ropes. “My general feeling, especially about Texas, is that there’s not a lot of community safety-netting when it comes to emergencies,” Davis says. “It feels like sort of every man for himself.”

Her sentiment fits with what the pollster Kristen Soltis Anderson calls a “cross-partisan rise in distrust” of institutions. Republicans and Democrats now share similar levels of distrust of Congress and big business. Americans on both the left and the right feel unsupported; preppers are just doing something about it. “There’s this common thread that I think unites preppers of all political persuasions, which is a lack of faith in political progress as a whole and a skepticism towards political leadership,” Mills told me. Conservative preppers were once worried about Barack Obama, and liberals are most worried about climate disasters, but they both worry that the government doesn’t have your back.

[Jonathan Chait: How liberal America came to its senses]

Some of my conversations with liberal preppers served as good reminders to buy bottled water and flashlights in case of a natural disaster, but some of them had an air of paranoia. Many of their worst-case scenarios seemed unlikely to ever take place. What are the odds that American citizens would actually be banned from international travel? What is the likelihood that Republicans would outlaw not just Plan B, but also birth control, which is used by 82 percent of reproductive-age women?

Then again, we live in outrageous times, during which a reality-TV host can become president, for the second time, after a failed coup attempt. That president picked another TV host to be in charge of the nation’s defense. His chosen health secretary has urged parents to ignore the CDC guidelines for childhood vaccinations. Abortion is completely banned in 12 states. There really has been a global pandemic that shut down much of the world for years. There’s a sense that literally anything can happen, so you’d better be prepared.

Gittinger pointed out that when the coronavirus pandemic broke out, she had N95 masks on hand. Who’s too paranoid now?

Three years ago, when it was trickling into the United States, the bird-flu virus that recently killed a man in Louisiana was, to most Americans, an obscure and distant threat. Now it has spread through all 50 states, affecting more than 100 million birds, most of them domestic poultry; nearly 1,000 herds of dairy cattle have been confirmed to be harboring the virus too. At least 66 Americans, most of them working in close contact with cows, have fallen sick. A full-blown H5N1 pandemic is not guaranteed—the CDC judges the risk of one developing to be “moderate.” But this virus is fundamentally more difficult to manage than even a few months ago and is now poised to become a persistent danger to people.

That didn’t have to be the reality for the United States. “The experiment of whether H5 can ever be successful in human populations is happening before our eyes,” Seema Lakdawala, a flu virologist at Emory University, told me. “And we are doing nothing to stop it.” The story of bird flu in this country could have been shorter. It could have involved far fewer cows. The U.S. has just chosen not to write it that way.

[Read: America’s infectious-disease barometer is off]

The USDA and the CDC have doggedly defended their response to H5N1, arguing that their interventions have been appropriately aggressive and timely. And governments, of course, don’t have complete control over outbreaks. But compared at least with the infectious threat most prominent in very recent memory, H5N1 should have been a manageable foe, experts outside of federal agencies told me. When SARS-CoV-2, the virus that sparked the coronavirus pandemic, first spilled into humans, almost nothing stood in its way. It was a brand-new pathogen, entering a population with no preexisting immunity, public awareness, tests, antivirals, or vaccines to fight it.

H5N1, meanwhile, is a flu virus that scientists have been studying since the 1990s, when it was first detected in Chinese fowl. It has spent decades triggering sporadic outbreaks in people. Researchers have tracked its movements in the wild and studied it in the lab; governments have stockpiled vaccines against it and have effective antivirals ready. And although this virus has proved itself capable of infiltrating us, and has continued to evolve, “this virus is still very much a bird virus,” Richard Webby, the director of the World Health Organization Collaborating Centre for Studies on the Ecology of Influenza in Animals and Birds, told me. It does not yet seem capable of moving efficiently between people, and may never develop the ability to. Most human cases in the United States have been linked to a clear animal source, and have not turned severe.

The U.S., in other words, might have routed the virus early on. Instead, agencies tasked with responding to outbreaks and upholding animal and human health held back on mitigation tactics—testing, surveillance, protective equipment, quarantines of potentially infected animals—from the very start. “We are underutilizing the tools available to us,” Carol Cardona, an avian-influenza expert at the University of Minnesota, told me. As the virus ripped through wild-animal populations, devastated the nation’s poultry, spilled into livestock, started infecting farmworkers, and accumulated mutations that signaled better adaptation to mammals, the country largely sat back and watched.

When I asked experts if the outbreak had a clear inflection point—a moment at which it was crucial for U.S. leaders to more concertedly intervene—nearly all of them pointed to the late winter or early spring of last year, when farmers and researchers first confirmed that H5N1 had breached the country’s cattle, in the Texas panhandle. This marked a tipping point. The jump into cattle, most likely from wild birds, is thought to have happened only once. It may have been impossible to prevent. But once a pathogen is in domestic animals, Lakdawala told me, “we as humans have a lot of control.” Officials could have immediately halted cow transport, and organized a careful and concerted cull of infected herds. Perhaps the virus “would never have spread past Texas” and neighboring regions, Lakdawala told me. Dozens of humans might not have been infected.

[Read: America’s bird-flu luck has officially run out]

Those sorts of interventions would have at least bought more of the nation time to provision farmworkers with information and protection, and perhaps develop a plan to strategically deploy vaccines. Government officials could also have purchased animals from the private sector to study how the virus was spreading, Cardona told me. “We could have figured it out,” she said. “By April, by May, we would have known how to control it.” This sliver of opportunity was narrow but clear, Sam Scarpino, an infectious-disease modeler and flu researcher at Northeastern University, whose team has been closely tracking a timeline of the American outbreak, told me. In hindsight, “realistically, that was probably our window,” he said. “We were just too slow.”

The virus, by contrast, picked up speed. By April, a human case had been identified in Texas; by the end of June, H5N1 had infected herds in at least a dozen states and more than 100 dairy farms. Now, less than 10 months after the USDA first announced the dairy outbreak, the number of herds affected is verging on 1,000—and those are just the ones that officials know about.

The USDA has repeatedly disputed that its response has been inadequate, pointing out to The Atlantic and other publications that it quickly initiated studies this past spring to monitor the virus’s movements through dairy herds. “It is patently false, and a significant discredit to the many scientists involved in this work, to say that USDA was slow to respond,” Eric Deeble, the USDA’s deputy undersecretary for marketing and regulatory programs, wrote in an email.

And the agency’s task was not an easy one: Cows had never been a known source of H5N1, and dairy farmers had never had to manage a disease like this. The best mitigation tactics were also commercially formidable. The most efficient ways to milk cows invariably send a plume of milk droplets into the air—and sanitizing equipment is cumbersome. Plus, “the dairy industry has been built around movement” of herds, a surefire way to move infections around too, Cardona told me. The dairy-worker population also includes many undocumented workers who have little incentive to disclose their infections, especially to government officials, or heed their advice. At the start of the outbreak, especially, “there was a dearth of trust,” Nirav Shah, the principal deputy director of the CDC, told me. “You don’t cure that overnight.” Even as, from the CDC’s perspective, that situation has improved, such attitudes have continued to impede efforts to deploy protective equipment on farms and catch infections, Shah acknowledged.

Last month, the USDA did announce a new plan to combat H5N1, which requires farms nationwide to comply with requests for milk testing. But Lakdawala and others still criticized the strategy as too little, too late. Although the USDA has called for farms with infected herds to enhance biosecurity, implementation is left up to the states. And even now, testing of individual cows is largely left up to the discretion of farmers. That leaves too few animals tested, Lakdawala said, and cloaks the virus’s true reach.

The USDA’s plan also aims to eliminate the virus from the nation’s dairy herds—a tall order, when no one knows exactly how many cattle have been affected or even how, exactly, the virus is moving among its hosts. “How do you get rid of something like this that’s now so widespread?” Webby told me. Eliminating the virus from cattle may no longer actually be an option. The virus also shows no signs of exiting bird populations—which have historically been responsible for the more severe cases of avian flu that have been detected among humans, including the lethal Louisiana case. With birds and cows both harboring the pathogen, “we’re really fighting a two-fronted battle,” Cardona told me.

Most of the experts I spoke with also expressed frustration that the CDC is still not offering farmworkers bird-flu-specific vaccines. When I asked Shah about this policy, he defended his agency’s focus on protective gear and antivirals, noting that worker safety remains “top of mind.” In the absence of consistently severe disease and evidence of person-to-person transmission, he told me, “it’s far from clear that vaccines are the right tool for the job.”

[Read: How much worse would a bird-flu pandemic be?]

With flu season well under way, getting farmworkers any flu vaccine is one of the most essential measures the country has to limit H5N1’s threat. The spread of seasonal flu will only complicate health officials’ ability to detect new H5N1 infections. And each time bird flu infects a person who’s already harboring a seasonal flu, the viruses will have the opportunity to swap genetic material, potentially speeding H5N1’s adaptation to us. Aubree Gordon, a flu epidemiologist at the University of Michigan, told me that’s her biggest worry now. Already, Lakdawala worries that some human-to-human transmission may be happening; the United States just hasn’t implemented the infrastructure to know. If and when testing finally confirms it, she told me, “I’m not going to be surprised.”