When World War II began, the US military discovered that it had a huge health problem: hepatitis. Nothing much was known about the disease and the military wanted to know how to prevent it and cure it.

So, from shortly after Pearl Harbor in 1942 to the end of the War and continuing to 1972, American biomedical researchers deliberately infected people with hepatitis. Government-sponsored researchers were attempting to discover the basic features of the disease and the viruses causing it, and to develop interventions that would quell recurring outbreaks.

A new book from Yale University Press, Dangerous Medicine: The Story behind Human Experiments with Hepatitis describes the medical and ethical issues behind hepatitis experiments.

Drawing from extensive archival research and in-person interviews, Professor Sydney Halpern traces the hepatitis program from its origins in World War II through its expansion during the initial Cold War years, to its demise in the early 1970s amid an outcry over research abuse.

The subjects in hepatitis studies were members of stigmatized groups—conscientious objectors, prison inmates, the mentally ill, and developmentally disabled adults and children.

The book reveals how researchers invoked military and scientific imperatives and the rhetoric of a common good to win support for the experiments and access to recruits. Halpern examines the participants’ long-term health consequences and raises troubling questions about hazardous human experiments aimed at controlling today’s epidemic diseases.

It makes grim reading. In some experiments, people were deliberately infected, either by injection or by drinking “milkshakes” containing hepatitis virus in the form of stool samples mixed with chocolate milk. At least four people died of forms of hepatitis during the experiments.

But there was no long-term follow-up and no one knows how many became disabled or died years later as a result of their infection.

The hepatitis experience raises many ethical questions. As a reviewer notes in Nature:

There was a time when we could have casually looked down our noses at mid-twentieth-century ignorance about infectious diseases. But with the world still in the throes of a coronavirus pandemic, I was struck by the parallels. Witness how efforts have been focused on the acute impacts of disease (hospitalization, death) without much thought to long-term consequences (disability). Or think of how those with the least agency — children, people in prison, people with severe mental illnesses — have been put at risk by those with the most power.

Formally, our approach to medical ethics has improved since the 1940s, but Halpern reminds us that many clinical trials in healthy individuals still rely on vulnerable populations. Some people move from one to the next in search of food, housing or remuneration in exchange for their participation. People in regions with poor access to health care sometimes have to enrol to get basic medical treatment. And in the United States, there is still no requirement to provide compensation for long-term disability that might arise from participation in clinical trials.

Dangerous Medicine is also a reminder of a catastrophic medical error involving vaccines. By the end of 1942, there were more than 300,000 cases of hepatitis in the military and scores had died. The War Department eventually had to withhold news of deaths on the grounds of national security. The cause of the epidemic, it turns out, was a contaminated yellow fever vaccine. Early in the War the Secretary of War, Henry L. Stimson, had mandated vaccination for all military personnel because his experts feared that Japan was weaponizing yellow fever as part of a germ warfare program. Ironically, to prevent a disease outbreak that never materialised, the US military ended up causing an epidemic of another disease.