After four decades of dedicated research on HIV, scientists have made extraordinary progress in treating the disease. But we still don’t have a vaccine or a cure. On today’s show, we’re joined by two veteran scientists who have dedicated their careers to HIV research. First up is Christine Rouzioux, a virologist from the Nobel Prize winning team of scientists who first identified the HIV virus. For the second half of the show we talk with Richard Koup from the National Institutes of Health, who explains why it’s so hard to create an HIV vaccine.