Marc Koska

In 1984, Marc Koska read an article that predicted HIV would spread widely through unsafe injections. Appalled at the prospect of such an avoidable catastrophe, he decided there and then to try and do something about it. The result is the K1 - a single-use syringe that has saved an estimated 15 million lives and counting.

But he hasn't stopped there: In 2005, he founded a nonprofit, SafePoint, which aims to educate people in the developing world about the dangers of reusing any instruments that come into contact with blood.