Amy Sussman/AP
Researchers are celebrating what looks like a major step on the road to eventually finding a cure for the AIDS virus. At an international AIDS conference Wednesday, it was announced that following bone-marrow transplants for blood cancers, two HIV-infected patients in Boston are now virus-free and off their antiretroviral drugs. International AIDS Society president Françoise Barré-Sinoussi, who discovered the virus that causes AIDS, called the Boston findings “very interesting and very encouraging,” though at this point it means little for the 34 million around the world living with HIV but not blood cancer and without access to the best doctors or hospitals. The technique used on the two Boston patients is also extremely dangerous—it involves weakening the immune system ahead of the transplant—to the point that it’s ethical only if performed on someone already likely to die from cancer.