Harald zur Hausen of Germany reacts after receiving the 2008 Nobel Prize in Medicine at the Concert Hall in Stockholm December 10, 2008. The medicine prize was given to three researchers, with zur Hausen awarded one half for his discovery of "human papilloma viruses causing cervical cancer" and one half shared by Francoise Barre-Sinoussi and Luc Montagnier of France for their discovery of the "human immunodeficiency virus". REUTERS/Bob Strong (SWEDEN)