Late last month, a conservative website called The Federalist published an article advocating that healthy, young Americans deliberately infect themselves with Covid-19, as part of a national “controlled voluntary infection” strategy meant to build “herd immunity.” If enough Americans expose themselves to the virus and become immune, the theory goes, the country would have a mobilized cadre of immune citizens. This immune elect could reopen businesses, return to work, and save the American economy.

The article was widely discredited by public health experts and economists, as both logically dubious and ethically specious, but such thinking has already metastasized. The likes of Glenn Beck and Lt. Gov. Dan Patrick of Texas have fashioned the willingness to endure a bout with coronavirus as a patriotic, pro-economy act; Germany, Italy, and Britain are all toying with notions of “immunity passports” — proof that a person has beaten Covid-19 — that would allow people with antibodies to go back to work faster.

That people could wield their hard-earned “immunocapital” to save the economy sounds like science fiction. But as we wait months or years for a viable vaccine, leveraging peoples’ antibodies may well be part of our economic strategy. If so, we should heed lessons from the past and beware of the potential social perils. As a historian, my research has focused on a time and place — the 19th-century Deep South — that once operated by a very similar logic, only with a far more lethal and fearsome virus: yellow fever. Immunity on a case-by-case basis did permit the economy to expand, but it did so unevenly: to the benefit of those already atop the social ladder, and at the expense of everyone else. When a raging virus collided with the forces of capitalism, immunological discrimination became just one more form of bias in a region already premised on racial, ethnic, gender and financial inequality.

Yellow fever, a mosquito-borne flavivirus, was inescapable in the 19th-century Deep South and a point of near-constant terror in New Orleans, the region’s hub. In the six decades between the Louisiana Purchase and the Civil War, New Orleans experienced 22 full-blown epidemics, cumulatively killing over 150,000 people. (Perhaps another 150,000 died in nearby American cities.) The virus killed about half of all those it infected and it killed them horribly, with many victims vomiting thick black blood, the consistency and color of coffee grounds. The lucky survivors became “acclimated,” or immune for life.