A great article by Charlie Jane Anders.
AIDS was a terrifying mystery, and then we solved it. When researchers identified the human immunodeficiency virus as the reason why young, previously healthy people were developing rare cancers and wasting away, it was a triumph of medical science.
But even as the medical community reached a consensus that HIV caused AIDS, a counter-movement was emerging, claiming that HIV didn’t exist, or that the virus existed but was harmless. The symptoms of AIDS, according to some of these people, were actually caused by HIV therapies themselves. To this day, some people continue to believe that HIV is a hoax.