What virus discovery earned Harald zur Hausen the 2008 Nobel Prize in Physiology or Medicine?

Harald zur Hausen won the 2008 Nobel Prize in Physiology or Medicine for discovering human papillomavirus (HPV) as a cause of cervical cancer.

Zur Hausen challenged the prevailing view that herpes simplex virus caused cervical cancer. By studying tumor cells, he identified HPV DNA in cervical cancer tissue and showed that certain high-risk types, especially HPV-16 and HPV-18, could drive malignant changes.

His work helped establish that infection with high-risk HPV is the central cause of nearly all cervical cancers. It also led to preventive HPV vaccines and supported the use of HPV testing in cervical-cancer screening.

A common mix-up is confusing the Nobel-recognized discovery with the vaccine itself. Zur Hausen received the prize for linking HPV to cervical cancer; vaccine development was a later medical and technological achievement involving many researchers.