A second woman appears to have eliminated HIV naturally and may even be considered cured. Last year, Xu Yu, MD, of Massachusetts General Hospital, and colleagues reported that Loreen Willenberg, dubbed “the San Francisco Patient,” appears to be cured without a stem cell transplant. Willenberg has maintained control of HIV for decades without antiretroviral therapy. The researchers were unable to find any intact HIV blueprints in more than 1.5 billion of her blood and gut cells, suggesting that her immune system may have eliminated the viral reservoir. Now, Yu’s team has reported that a second woman, “the Esperanza Patient,” who received antivirals for only six months during pregnancy, had no intact viral genomes in more than 1.19 billion blood cells and 500 million placenta tissue cells. Yu suggests that a specific type of killer T-cell response common to both patients may be driving these outcomes. If these immune mechanisms can be better understood, researchers may be able to develop therapies that mimic them.