In the past two days alone, two African-American NBA basketball players have tested positive for coronavirus, and several cases have turned up among native populations in both African and Caribbean countries, puncturing any theory that black people are immune to the disease. Yet the memes persist.

Statements like this one are surely made in jest. But there are at least some instances of actual scientific or medical arguments, which outlets including Reuters and Politifact have already debunked. While some may argue that the jokes, at least, are harmless, U.S. history evinces how unsubstantiated claims about race-based resilience to disease have led to devastating outcomes, particularly for African Americans. The impacts of such beliefs still affect how people of color are medically treated—or not—today.

The 18th-century yellow fever outbreak in the Americas is instructive here. In the 1740s, yellow fever had overtaken coastal port cities such as Charleston, South Carolina, driving people into delirium, endless vomiting, hemorrhaging, and eventually death. The physician John Lining recorded his observations about the disease in Charleston after inspecting slave ships and their cargo—including captive Africans—finding that it was almost exclusively white people who were succumbing to the disease. These observations helped reinforce already-stirring beliefs that Africans had some kind of supernatural inoculation to some of the deadliest diseases floating along the American coast.

Lining’s medical briefs became the reference manuals for another physician, Dr. Benjamin Rush, when in 1793 a yellow fever outbreak took hold of Philadelphia, Pennsylvania, which at the time was the nation’s capitol. Close to 20,000 people — half of the population — fled Philly that year, while many African Americans actually stayed in the city at the request of Rush, who wanted to train them to nurse, care-take, and dig graves for the thousands of people dying of yellow fever.