Meanwhile, Zur Hausen was rewarded for his work on what is sometimes called "the silent killer" of women because it is often undetected until it is too late.

"His discovery has led to characterisation of the natural history of human papilloma virus (HPV) infection, and understanding of mechanisms of HPV-induced carcinogenesis and the development of prophylactic vaccines against HPV acquisition," the jury said.

It pointed out that five per cent of cancers worldwide were caused by the virus. Fifty to 80 per cent of the population is infected with the virus, though not all infections are cancerous.

Infectious cancer agents

"This prize means a great deal to me because on the one hand an area has been recognised that has increasingly moved to the forefront in cancer research, namely the role of infectious agents," Zur Hausen, 72, said in an interview with German television.

Today, a simple smear test can detect HPV and there are two effective vaccines against it.

Zur Hausen is a professor emeritus and former chairman and scientific director of the German Cancer Research Centre in Heidelberg.

The laureates will receive a gold medal, a diploma and 10 million Swedish kronor (US$1.42 million, A$1.97 million) _ half for Zur Hausen and half for the French pair _ at a formal ceremony in Stockholm on 10 December.