HIV vaccine: After 25 years of failure, an experimental drug offers hope

Nearly 30 years after its discovery, AIDS still has no known cure. Researchers almost gave up hope of ever finding a vaccine. However, hopes were rekindled when a Phase III clinical trial involving more than 16,000 adult volunteers in Thailand demonstrated that an experimental HIV vaccine was safe and modestly effective, preventing HIV infection in 31.2 percent of cases.

That's a step in the right direction, but those are modest results; for any other disease, preventing infection in fewer than a third of the tested cases wouldn't arouse much hype or hope. But with the HIV virus, after 25 years of attempts and failures, some fairly recent, it's no wonder everybody is excited for this potential breakthrough.