1 in 8 cancers are caused by infections? What the WHO estimate really means
- Claim
- ONE IN EIGHT CANCERS?
- Catch
- IT'S A MODEL
- Verdict
- A MAP, NOT A CONTAGION
A worldwide analysis from the World Health Organization's cancer agency (IARC), published in The Lancet Oncology, estimates that 2.3 million new cancer cases in 2024 were attributable to infections. That is 12% of all cancer cases, or roughly 1 in 8. The analysis used GLOBOCAN 2024 cancer incidence data and estimated population-attributable fractions for 12 infectious agents classified as Group 1 carcinogens by the IARC Monographs Programme. Five pathogens accounted for most of the burden: Helicobacter pylori (760,000 cases, 4% of all cancers), human papillomavirus or HPV (750,000, 4%), hepatitis B virus (360,000, 2%), Epstein-Barr virus (260,000, 1%) and hepatitis C virus (160,000, under 1%). The largest regional burden was in eastern Asia, with 990,000 cases (42% of the global total). The authors argue the findings make a case for prevention: HPV and hepatitis B vaccination, testing and treatment of HIV, H. pylori, hepatitis B and hepatitis C, safe injection practices, condoms and pre-exposure prophylaxis for HIV, and screening for precancerous cervical and anal lesions. The catch: these are modelled estimates, not a count of tumours actually caused by an infection. Population-attributable fractions depend on registry data and on assumptions about what share of each cancer type an infection explains, and the authors say the 12% should not be compared with earlier estimates (such as 18% in 2002), because the data and methods changed. Having an infection does not mean you will get cancer, and cancer itself is not contagious.
SOURCES
- Rumgay, H., Georges, D., Huang, Y., Hirabayashi, M., Shah, R., de Martel, C., Park, J. Y., Soerjomataram, I., & Clifford, G. M. (2026), "Global burden of cancer attributable to infections in 2024: a worldwide incidence analysis," The Lancet Oncology, 27(10), 1237-1248. DOI: 10.1016/S1470-2045(26)00307-4
- La Marca, J. & Diepstraten, S. (September 29, 2026), "One in eight cancers are likely caused by an infection worldwide - new study," The Conversation
For information only, not medical advice. If you have questions about vaccination, hepatitis, H. pylori or cancer screening, talk to a doctor.
