1 OCT 2026 — An analysis by the World Health Organization's cancer agency, published in The Lancet Oncology, attributes about 2.3 million new cancer cases worldwide in 2024, roughly one in eight, to infections. Many could be prevented with tools that already exist, such as vaccines and treatment for the infections, the authors say.
Southeast Asia carries a larger share than the world as a whole, with 16% of its cancers attributed to infections against 12% globally.
Five infections dominate
The International Agency for Research on Cancer (IARC) team estimated the share of cancers caused by 12 infectious agents it classes as definite carcinogens. Five account for most of the total, the paper reports: the stomach bacterium Helicobacter pylori (760,000 cases), human papillomavirus or HPV (750,000), hepatitis B (360,000), Epstein-Barr virus or EBV (260,000) and hepatitis C (160,000).
All cervical cancer, about 600,000 cases, is attributed to HPV. Hepatitis B is linked to about half of hepatocellular carcinoma, the most common liver cancer, and hepatitis C to a fifth. EBV is linked to 88% of nasopharyngeal cancer, a cancer of the upper throat behind the nose.
The picture in Asia
Eastern Asia carries the largest burden, with 990,000 cases, 42% of the world total, at an age-standardised rate of 31.9 per 100,000, driven mainly by H. pylori and hepatitis B. Mongolia, Japan and South Korea have particularly high rates of H. pylori-linked cancer, the paper says.
Southeast Asia's rate, 23.1 per 100,000, is above the global average of 22.7. EBV causes about 34,000 cancers a year in the region, and 80% of those are nasopharyngeal, a much higher share than in eastern Asia, where stomach cancers make up nearly half of EBV-linked cases. The authors also count two liver flukes, parasites caught from raw freshwater fish, among the causes of bile duct cancer.
Prevention exists for most of it
The authors list proven but underused measures: HPV and hepatitis B vaccination; testing and treating H. pylori, hepatitis B and C and HIV; safe injection practices; HIV prevention; and screening for precancerous cervical and anal lesions. Hepatitis C can now be cured with a short course of antiviral drugs.
The gap: Epstein-Barr virus
There is no EBV vaccine, which the authors single out as a case for investment in new prevention tools. That gap matters most in places such as Southeast Asia, where EBV-linked nasopharyngeal cancer is common.
How to read the numbers
The estimates rest on the GLOBOCAN database of cancer incidence, which the authors note has gaps in coverage and data quality, especially in under-represented regions. That could push the true burden either up or down.
The total is close to the agency's previous estimate of 2.2 million for 2018, but the two are not directly comparable. The new analysis adds 16 infection–cancer pairs that the earlier one did not include, such as cancers caused by HIV and by Merkel cell polyomavirus. Hackensack Meridian Health, a US hospital group, publicised the findings on 30 September.
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