Two weeks ago, by inserting what must be the most notorious asterisk in modern public health, the Centers for Disease Control and Prevention caveated its long-standing position that vaccines do not cause autism. Under the direction of Robert F. Kennedy, Jr., the Secretary of Health and Human Services, a C.D.C. web page now contends that this is “not an evidence-based claim” and that research linking vaccines to autism has been “ignored by health authorities.” The fact that the original statement remains at all is due to an agreement with Senator Bill Cassidy, a physician and the chair of the Senate health committee, who disregarded decades of Kennedy’s vaccine skepticism to advance his confirmation after extracting a set of flimsy commitments that Kennedy is now betraying. The Autism Science Foundation said that it is “appalled” by the C.D.C.’s new stance; the American Medical Association warned of “dangerous consequences.”

The Department of Health and Human Services maintains that it is hewing to “gold standard, evidence-based science”—a piece of doublespeak so thick that it might unsettle Orwell. Discounting dozens of rigorous studies that have analyzed millions of patients and failed to connect vaccines to autism, the C.D.C. website claims that about half of parents of children with autism believe vaccines contributed to that autism. It cited a decades-old paper that surveyed a few dozen parents who strongly embraced alternative medicine, at two private practices in the Northeast. The web page points out that autism rates have risen in recent decades and so has the number of infant vaccinations—an observation that might also be made about prestige TV shows and pumpkin-spice lattes. The H.H.S. will now provide “appropriate funding” for studies on vaccines and autism, and last week it appointed a physician with a history of vaccine skepticism as the second-in-command at the C.D.C. The episode puts to rest any doubts about whether Americans can still trust information from the nation’s top health agency.

At stake is a question of the quality of information that should be taken seriously in public discourse and how that information should be communicated. Science may be the most powerful engine for grasping reality, but it suffers a rhetorical disadvantage. In science, the burden of proof falls on the one aiming to overturn the “null hypothesis”—the default position that one thing doesn’t cause another. But conspiratorial thinking is fuelled by the inverse: self-assured conjecture that demands a level of refutation no amount of evidence can offer. Proving the absence of a connection will always be harder than speculating about its existence. The language of science is measured and provisional; the language of politics is declarative and bombastic. In September, President Donald Trump told pregnant women to “fight like hell” not to take Tylenol, because of a potentially increased risk of autism in children; his Food and Drug Administration clarified that “a causal relationship has not been established and there are contrary studies in the scientific literature.” Tylenol, the agency wrote, remains “the safest over-the-counter” option for treating fever or pain.

The privilege that American scientists have taken for granted—one that is now being trampled—is the ability to go about their work free of political interference. With few exceptions, both Republicans and Democrats have supported independent science, understanding that the nation benefits from research that promotes health, innovation, and economic growth. But since Trump returned to office his Administration has fired or muzzled government scientists with disfavored views on nutrition and climate change; cancelled funding for long-running surveys on food insecurity and global health; dismissed independent committees focussed on air pollution, health-care disparities, and hospital infections; and pulled support for research into vaccines. This month, leading members of the National Institutes of Health, who ascended to their roles in large part based on their criticism of COVID-era mandates, published an article arguing that we should plan for the next pandemic not by trying to identify dangerous pathogens or by developing vaccines and medications to mitigate their damage but by encouraging people to be healthier: by abstaining from smoking, by eating nutritious food, and by “getting up and walking more.”

“The best pandemic preparedness playbook,” the authors wrote, unironically, “is making America healthy again.” Leaving aside that mRNA vaccines saved millions of lives during the covid pandemic, and that a society might like to prepare both by promoting healthy habits and by investing in biotechnology, this ignores the fact that, in some outbreaks, young and healthy people have had among the highest rates of death, and that with any infectious disease many people will remain vulnerable no matter what they do. (This year, a variant of the H3N2 influenza virus, known as subclade K, has caused a surge in cases in the United Kingdom, Canada, and Japan, and appears to be most perilous for children and older adults.) The unpredictability of pathogens is precisely why a broad-based strategy is needed. Pushups won’t save you from Ebola.

In the nineteen-thirties, a Soviet biologist named Trofim Lysenko gained the patronage of Joseph Stalin. Lysenko, who was tapped to guide the country’s agricultural reforms, had a range of pseudoscientific ideas, including that the environment, not genes, primarily determined an organism’s traits and that members of the same species don’t compete. He oversaw a series of biologically wrongheaded programs that contributed to famine, misery, and death for millions of people. (A British botanist once said that talking to Lysenko “was like trying to explain differential calculus to a man who didn’t know his twelve times table.”) With Stalin’s backing, Lysenko purged scientists who disagreed with him and set the country’s once preëminent genetics research back by decades.

A reason that the U.S. became the world’s biomedical leader—indeed, a reason that it emerged from the Cold War victorious—is that democratic governance allows for a level of self-correction that authoritarianism does not. Bad ideas can be beaten back at the ballot box, in the public square, and through the halls of Congress. The country is under no obligation to tolerate institutionalized quackery or elected officials who, through feckless appeals and half measures, have become complicit in it. Truly making America healthy will involve more than removing an asterisk. It will require turning the page. ♦