Helene Gayle is an AIDS expert who has been working in many different initiatives in the US, among them the Centers for Disease Control (CDC). She also works in President Obama's advisory group on HIV/AIDS. Here she talks about understanding and changing behaviors.

Dr Robert Gallo is interviewed in the laboratory about the HIV virus and his ongoing work. He also talks with his team and discusses the question of international collaboration with Lars Olof Kallings. He answers questions about HIV and AIDS, drugs and promiscuity.