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Around one in eight new cancer cases worldwide in 2024 was linked to an infection — and most of those cancers could have been avoided with vaccines, screening, or straightforward treatment. That is the striking conclusion of a new analysis in The Lancet Oncology by researchers at the World Health Organization's International Agency for Research on Cancer, led by epidemiologist Harriet Rumgay, which estimated that 2.3 million cancer diagnoses — 12% of the global total — were attributable to infections.
The five pathogens behind the numbers
The team examined 12 infectious agents classified as carcinogens, and found that just five drove nearly the entire burden. Helicobacter pylori — the stomach bacterium carried, often silently, by a huge share of humanity — accounted for about 760,000 cases, mostly gastric cancers. Human papillomavirus followed with roughly 750,000 cases, overwhelmingly cervical cancer. Hepatitis B virus was linked to about 360,000 cases, mostly liver cancer. The Epstein-Barr virus, which causes glandular fever, contributed around 260,000 cases, including nasopharyngeal cancers and lymphomas. And hepatitis C added about 160,000 cases, again mostly liver cancer. Together the five pathogens were tied to 20 different cancer types, according to reports from CNN, Live Science and medical outlets covering the study.
An unequal burden
The geography is stark. More than three-quarters of infection-related cancers occurred in low- and middle-income countries. Eastern Asia carried the largest share — about 990,000 cases, 42% of the global total — while rates also ran above the global average in sub-Saharan Africa, central and eastern Europe, and southeastern Asia. The gap is not biology but access: where infection prevalence is high and vaccination, screening and treatment are thin, cancers follow. The study's senior author, epidemiologist Gary Clifford, put the challenge plainly in comments reported by CNN: "We just need the politics and the finances and the buy-in from the public and the communication to get the programmes implemented. Prevention works."
The prevention toolbox already exists
Here is what makes the findings hopeful rather than just alarming: the tools to stop most of these cancers already exist. HPV and hepatitis B vaccines are highly effective — countries with high coverage are already seeing cervical cancer begin to disappear. A breath or stool test can find H. pylori, and antibiotics can clear it. Cervical screening catches precancerous changes before they turn. And while there is no hepatitis C vaccine, antiviral medicines now cure most infections. The weak link is coverage: only 31% of eligible adolescent girls worldwide had received even one HPV dose in 2024, far below the WHO's 90% target, and there is still no approved vaccine for EBV.
Infections do not make cancer inevitable — long-term inflammation or cellular damage from a persistent infection is what raises the risk over years. But the study's message is a profound one: millions of future cancer diagnoses are, in principle, optional. The question is whether the world will pay for the prevention it already knows how to deliver.
This article is general information only and is not medical advice.
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