Big advances in AIDS research are hard to come by—but researchers in Oregon say their new vaccine marks a huge step forward. In a study of HIV’s monkey equivalent, the researchers found that 13 of 24 rhesus macaques given the vaccine were protected against the disease; 12 were still protected a year later, reports the BBC. The vaccine contained a genetically-altered version of the virus, which prompted the production of special blood cells that stick around well after a disease is conquered.
The cells are ready to fight again if needed, a researcher says: “There are soldiers that are back at the base with their rifles in the shed, and then you have the guys out in the field.” Other researchers were impressed with the finding, but concerned about its safety for humans. The genetically-modified version of the virus, called CMV, “does cause a number of diseases,” says one. “If you're giving people something you're not going to be able to get rid of should it cause problems, then that's quite a difficult risk to manage.”