Three people, including two children, died of measles in the United States in 2025. Their deaths could have been prevented. Last year, there were 2.267 confirmed cases of measles in the United States — more than seven times the 285 cases reported in 2024, and the highest number in 30 years or more. All of these cases could have also been prevented. So why weren't they?
For two decades, Robert F. Kennedy Jr. (confirmed as Secretary of the U.S. Department of Health and Human Services last February) promoted unfounded theories linking vaccines to autism. He claimed that vaccines had "poisoned an entire generation of American children," and his statements likely contributed to the decline in vaccination rates in the United States. This led to a sharp increase in the incidence of measles.
Since taking office, Kennedy has fired experienced scientists from a key vaccine advisory board and replaced them with skeptics. He has also withdrawn funding for mRNA vaccine development, a method of developing new vaccines that has allowed for the rapid production of highly effective vaccines against Covid-19, likely saving millions of lives. Kennedy has suggested taking vitamin A as an alternative to the measles vaccine, after which some parents in Texas gave their children such high doses that they showed symptoms of poisoning.
Deviation from conventional scientific standards in public health is not just an American problem. In Slovakia, Prime Minister Robert Fico appointed Peter Kotlar, an orthopedic surgeon and anti-vaccine activist, to examine the country’s response to the pandemic. Kotlar’s October 2024 report described Covid-19 as “an act of bioterrorism” designed to “test the naivety of the global population to subconsciously follow orders.” The report also claimed, without any evidence, that mRNA vaccines alter human DNA and recommended that they be banned.
In a free society, individuals can express their unfounded views on vaccines, knowledgeable scientists can refute them, and public health officials should consider the evidence and act accordingly. In rare cases, views that run counter to the scientific consensus will turn out to be true and become the new orthodoxy.
Public health officials hold positions of special responsibility, shaping policies that affect millions of people. Vaccines are among the most extensively tested medical interventions in history. Yet vaccine skeptics, like Kennedy, demand more and more studies while accepting far lower standards of evidence for their claims—anecdote, selectively chosen data, and conspiracy theories about pharmaceutical companies.
When vaccination coverage falls below critical thresholds, “herd immunity” (the protection that vulnerable populations receive from high vaccination rates in the general population) is lost, and preventable diseases return. We know this from historical experience and from modern examples such as Romania and now Canada, where smallpox was considered eradicated.
In Romania, vaccination of children was mandatory under communism, and measles was effectively eradicated. While the fall of the Ceausescu dictatorship brought welcome freedoms and EU membership improved living standards, one consequence was that some vaccinations became voluntary. By 2023, the measles vaccination rate in Romania had fallen to 62%, down from 95% when the vaccine was introduced, and in 2024 the country recorded more than 30.000 cases of measles, including 23 deaths.
Some officials argue that they are simply respecting individual freedom. But the freedom of adults capable of making their own decisions does not extend to decisions that harm others. Refusing to vaccinate children does just that. Children in kindergarten or elementary school should be vaccinated not only because it will protect them, and because they are too young to make their own decisions, but also because refusing to vaccinate increases the risk to other children who are too young to be vaccinated, to immunocompromised people who cannot receive vaccines, and to the wider community when herd immunity collapses.
Kennedy presents himself as a fighter against the power of pharmaceutical companies, citing real scandals like Purdue Pharma’s promotion of OxyContin. But well-documented cases of corporate wrongdoing do not justify rejecting an entire category of medical interventions supported by scientific evidence of safety and effectiveness from independent researchers, public health agencies around the world, and decades of population-level data. The claim that this global scientific consensus is some vast conspiracy is utterly implausible.
When government officials act on unfounded beliefs about the risks of vaccines, people die, as did unvaccinated children in Texas who died of measles. Those who have power over health policy bear responsibility for such outcomes. Epistemic recklessness—the persistence of beliefs that are contrary to overwhelming evidence, when many lives depend on making the right judgment—is a fundamental ethical failing.
Of course, scientific understanding is never perfect or conclusive. The real questions about vaccine safety deserve serious scrutiny—that's why there are systems to monitor vaccine safety and why rare side effects are carefully studied. But there's a big gap between good-faith research and ideological resistance to the overwhelming body of evidence.
Anti-vaccinationists' disregard for scientific evidence is now producing exactly the harms that experts predicted: outbreaks of disease, preventable deaths, and the reversal of decades of public health progress. It must be stopped now, before the consequences become truly catastrophic.
Governments should appoint officials with relevant scientific and expert knowledge, who respect the evidence. Public health agencies should operate in accordance with scientific consensus, not political ideology. And when officials demonstrate a sustained commitment to views that contradict the evidence, they should be removed from positions where they can translate such views into policies with deadly consequences.
The author is Professor Emeritus of Bioethics at Princeton University; is the founder of the non-profit organization The Life You Can Save
Copyright: Project Syndicate, 2026. (translation: NR)
Bonus video:
