Two Scientists, Two Legacies: What Bill Foege and Peter Duesberg Teach Us About the Responsibilities of Expertise

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In the span of a single week in January, public health lost two scientists whose lives and careers could not have pointed in more different directions. Bill Foege, the former CDC director who helped lead the global eradication of smallpox and spent his career building institutions, mentoring leaders, and insisting that evidence and humility are not obstacles to action but the very conditions that make meaningful action possible, died on January 24. One week earlier, Peter Duesberg — once a celebrated virologist whose early work demonstrating that viruses can cause cancer earned him significant scientific recognition — died having spent the final decades of his career denying that HIV causes AIDS, a position that shaped policy in South Africa during the early 2000s and contributed, by credible scholarly estimates, to hundreds of thousands of preventable deaths.

Placing these two men in the same sentence might seem uncharitable to one or unfair to the other. But I think they belong together precisely because the contrast between them illuminates something important about the responsibilities that attach to scientific expertise, and about the consequences — not merely for careers or reputations, but for living human beings — when those responsibilities are honored or abandoned.

What Foege Built

Foege’s contribution to public health is almost impossible to overstate. The eradication of smallpox, which he helped engineer through the strategy of surveillance and containment — targeting vaccination at the contacts of known cases rather than attempting universal simultaneous immunization across vast populations — remains one of the greatest achievements in the history of medicine. It was an achievement born not from certainty but from creative uncertainty: the willingness to try a strategy that had not been proven at scale, in conditions of extraordinary logistical difficulty, guided by systematic evidence gathering and rapid adaptation.

But Foege’s legacy is not only strategic. It is moral and pedagogical. He believed, and said repeatedly, that certainty is dangerous and kindness is essential — that the public health practitioner’s job is to hold two things at once: rigorous commitment to evidence and deep humility about the limits of what we know. He used language to build trust, to share credit widely, and to widen the circle of care to include the most vulnerable. He never stopped reminding the people he trained that the goal was not to be right; it was to reduce suffering.

In a 2016 graduation speech at Emory University that I urge everyone to take 25 minutes to watch, Foege said something that has stayed with me: “I keep wondering why I was not born in a village in New Guinea. I am no self-made person. I was born in this country, urged on by family, traveled roads paid for by government, went to schools that required thousands of people to put together … I avoided dying of tuberculosis, food poisoning, toxic water because of a government, rarely appreciated. Not because I deserved it but because of a coalition of government, religious institutions, and public and private groups, all conspiring to help me.” That is the voice of a man who understood his work as a form of reciprocity — a debt owed to the systems and communities that made his life and career possible.

What Duesberg Chose

Duesberg’s early scientific career was genuinely distinguished. His research identifying oncogenes — genes that, when mutated or overexpressed, can drive the development of cancer — was foundational work that contributed to fields still active today. He had every credential required to be a trusted scientific voice. What he did with that trust is a story that should be studied by anyone who believes that expertise confers not just authority but obligation.

Beginning in the late 1980s, Duesberg rejected the emerging scientific consensus that HIV causes AIDS, arguing instead that the disease resulted from drug use, malnutrition, and other lifestyle factors. As evidence for the causal role of HIV accumulated — evidence that ultimately became overwhelming, replicated across thousands of studies in dozens of countries — Duesberg did not revise his position. He amplified it, lending his scientific credentials to arguments that encouraged people living with HIV to refuse antiretroviral treatment and that influenced the government of South Africa under President Thabo Mbeki to delay implementing programs that could have saved hundreds of thousands of lives.

What makes the Duesberg case instructive, rather than simply tragic, is that it illustrates a specific failure mode: the point at which healthy scientific skepticism — which is essential and admirable — curdles into something else. Skepticism is the engine of good science. It demands evidence, questions assumptions, and refuses to accept conclusions on the basis of authority alone. But skepticism exercised without the corresponding commitment to update one’s views when evidence accumulates is no longer skepticism. It is ideology wearing the costume of science. And ideology, when it carries the imprimatur of genuine credentials, can be extraordinarily dangerous.

The Lesson That Connects Them

I have been thinking about Foege and Duesberg in the context of this particular moment in American public health, because the questions their lives raise feel urgently relevant. Public health institutions are under pressure from multiple directions simultaneously: from political actors who distrust scientific consensus, from a media environment that rewards controversy over careful explanation, and from a segment of the scientific community that sometimes mistakes contrarianism for rigor. In that environment, it matters enormously which models of scientific practice and public communication we choose to honor and emulate.

Foege offers one model: evidence-driven, humble, deeply committed to equity and collective action, willing to say “I don’t know” and “we need to try this” in the same breath. Duesberg offers another: initially credentialed and rigorous, ultimately captured by certainty, willing to use the language of science to advance conclusions that the evidence did not support, and unable or unwilling to acknowledge the human cost of being wrong.

The former CDC Director once said, “Bet on the optimists. You need the optimist to say, ‘We’re going to try to do it.'” That is not naive optimism, uncoupled from evidence and consequence. It is the optimism of someone who has seen what is possible when human beings commit collectively to reducing suffering, guided by data, humility, and care. It is the only kind of optimism that public health can afford — and the only kind, I believe, that deserves the name.

Bill Foege spent his life building that case through his actions. It is our responsibility, in this moment of genuine difficulty for public health, to honor it.