One in eight cancers diagnosed worldwide last year trace back to an infection, and most of those cases could have been stopped with a vaccine, a test, or a simple course of treatment.
Story Snapshot
- A new study from the International Agency for Research on Cancer found that about 2.3 million new cancer cases in 2024, roughly 12% of the global total, are linked to infections.
- Twelve infectious agents, including viruses, a bacterium, and parasites, were counted in the analysis.
- Helicobacter pylori bacteria topped the list with about 760,000 cases, followed by HPV at 750,000, hepatitis B at 360,000, Epstein-Barr virus at 260,000, and hepatitis C at 160,000.
- Researchers point to vaccines, screening, and infection treatment as the main tools for cutting this burden down.
What The Global Study Actually Found
The research comes from the International Agency for Research on Cancer (IARC), part of the World Health Organization system, and was published in The Lancet Oncology. Scientists used IARC’s Global Cancer Observatory database to estimate how many 2024 cancer cases can be traced to 12 infectious agents already proven to cause cancer in humans. The answer: about 2.3 million cases, or close to one in eight diagnoses worldwide.
That number is not new territory for IARC. The agency estimated 2.2 million infection-linked cases for 2018, about 13% of all cancers that year, and roughly 2.3 million cases, or 12%, for 2020. The 2024 figure lands right in that same range, showing a burden that has stayed remarkably steady even as the list of known cancer-causing infections keeps growing.
Five Pathogens Drive Most Of The Burden
Stomach-dwelling Helicobacter pylori bacteria caused the most damage, linked to about 760,000 cancer cases in 2024. HPV came close behind at 750,000 cases, mostly tied to cervical cancer. Hepatitis B accounted for roughly 360,000 cases, Epstein-Barr virus for about 260,000, and hepatitis C for around 160,000. Together those five agents make up the overwhelming share of the global total, though the study tracked seven additional agents as well.
The analysis also widened its scope beyond past versions. It now folds in HIV, Merkel cell polyomavirus, and a newly confirmed link between Epstein-Barr virus and stomach cancer. IARC says these additions reflect evidence that has firmed up in recent years, not a change in how aggressively researchers are hunting for connections.
Why Prevention Is The Real Headline
What separates infection-driven cancer from most other cancer causes is that it can often be stopped before it starts. IARC researchers point to HPV vaccination, cervical cancer screening, hepatitis B vaccination, and testing and treatment for H. pylori as proven tools already in use around the world. None of these are new inventions. The gap is access, not science.
That access gap shows up starkly between wealthy and poor nations. Countries with strong vaccination programs and routine screening catch and stop many of these cancers before they ever register as a diagnosis. Countries without that infrastructure absorb a heavier share of the 2.3 million cases, even though the infections driving them are the same ones a vaccine or a simple blood test could catch early.
How This Fits The Bigger Picture
Cancer researchers have tracked infection-related cancer for decades, and this study extends a pattern rather than breaking new ground. The percentage has hovered near one in eight or one in nine for years, even as scientists add new pathogens to the list and refine their models. What changes year to year is less the size of the burden and more the precision of the map researchers use to target it.
For American readers, the practical takeaway is straightforward. Hepatitis B shots, HPV vaccines, and H. pylori testing are already standard options at most doctor’s offices. The World Health Organization’s own data makes the case that skipping them carries a measurable cost, not an abstract one. Cancer prevention tied to infection control stands out as one of the rare public health wins where the tools already exist and simply need to reach more people.
🦠Did you know that around one in eight cancers is linked to infections?
Understanding infection-related cancer risks highlights the importance of prevention, vaccination and early detection.
đź”— https://t.co/7G5lqU6mrr#CancerPrevention #PublicHealth #PersonalisedMedicine pic.twitter.com/6yPUaQ2IJO
— International Alliance for Personalised Medicine (@united4cancer) October 12, 2026
Coverage of the study from outlets including CBC and Newsweek echoed the same one-in-eight figure, underscoring that the finding has already become a reference point in global health reporting. The consistency across outlets and years gives the public a clear, stable number to work from as health agencies push for wider vaccination and screening access.
Sources:
time.com, iarc.who.int, gco.iarc.who.int
