New research shows one in eight cancers worldwide are caused by infections, with an estimated 2.3 million new cancer cases in 2024 linked to infectious agents. The study, published in The Lancet Oncology, was conducted by researchers at The International Agency for Research on Cancer (IARC), an arm of the World Health Organization.

The largest number of cases were caused by the bacterium Helicobacter pylori, accounting for 760,000 cases, predominantly in eastern Asia. Human papillomavirus (HPV) followed, causing 100% of cervical cancer cases and accounting for nearly 750,000 new cases globally, with high rates in sub-Saharan Africa. Hepatitis B virus (HBV) and hepatitis C virus (HCV) were linked to significant numbers of liver cancer cases.

For the first time, researchers expanded their list to include 16 additional cancers linked to infections, including HIV and Merkel cell polyomavirus. Epstein-Barr virus (EBV) was linked to about 260,000 cases globally, leading to nasopharyngeal cancer, some gastric cancers, and Hodgkin's lymphoma. Unlike other infections, there are no vaccines or antibiotic treatments for EBV.

The global report highlights vast regional differences, with high-income countries doing better due to established screening and vaccination programs, while lower-resourced countries face limited access to prevention and treatment.