Approximately 15% of all cancers were attributable to infectious agents such as helicobacter pylori, human papilloma virus (HPV), hepatitis B and C, and Epstein-Barr virus. The fraction of infection-attributable cancers varied between countries and development status, from less than 5% in Australia, Canada, New Zealand, the United States and select countries in western and northern Europe to more than 50% in some countries in sub-Saharan Africa. Two-thirds of infection-attributable cancers (1.4 million cases) occur in less developed countries. Vaccines are available for hepatitis B virus and some types of HPV and can reduce the risk of liver and cervical cancers, respectively