"It is tempting to see this moment as a crisis—perhaps even an unraveling. But history tells a different story."

HIV is spread by bodily fluids such as blood, breast milk or semen. It gradually weakens the body’s immune system and makes it vulnerable to disease, including ones rarely seen in otherwise healthy people. The surprising emergence of such cases in the 1980s is what tipped off health experts to what became known as the AIDS epidemic.