Just 5 Infections Responsible For More Than 2 Million New Cancer Cases Annually
NEWS | 29 September 2026
Cancer may seem like an inevitable part of life, but there are so many factors that can help reduce your risk. When we think about reducing cancer risk, we usually think of lifestyle factors: smoking, alcohol consumption, exercise. But a new study by a team of cancer epidemiologists, published in The Lancet Oncology, highlights just how much infections actually contribute to your cancer risk. Based on global data, infections were linked to 12 percent of all cancers that were diagnosed in 2024. That's 2.3 million new cancer cases. Five key pathogens were responsible for nearly all of those infection-linked cases. The most common offender was a stomach bacterium, Helicobacter pylori, which was involved in 4 percent of the total cancers diagnosed in 2024 – that's 760,000 cases. H. pylori is a really common bug: statistically speaking, every second person in the world is infected with it. For most people, infection with H. pylori causes no symptoms, but certain strains can cause gastric ulcers and ultimately stomach cancers. The human papillomavirus (HPV) was also linked to 4 percent of the total new cancers diagnosed in 2024, which is 750,000 cases. frameborder="0″ allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" referrerpolicy="strict-origin-when-cross-origin" allowfullscreen> Hepatitis B virus (HBV) was linked to 2 percent of new cases, Epstein-Barr virus (EBV) was linked to 1 percent, and hepatitis C virus (HCV) was linked to less than 1 percent. EBV is a newcomer to this list. Since previous global estimates were published, the evidence that EBV causes cancer has grown substantially. It's pretty freaky to think that these infections, which can already make us very sick in their own right, could also lead to cancer, but these findings also give us an opportunity. They suggest proper treatment and prevention of these infections could make a really big difference to cancer rates across the world. "Our updated estimates highlight the continued importance of infection control in global cancer prevention strategies," lead author Harriet Rumgay and her colleagues note. "Many carcinogenic infectious agents have existing or potential preventive interventions, including vaccines, diagnostics, treatments, and safe injection practices." For many of these pathogens, it's a matter of actually getting those public health interventions to people. "Despite progress in vaccination and screening, infection-related cancers remain a major challenge globally, with persistent inequities especially impacting low-income and middle-income countries," the authors add. Three-quarters of infection-related cancers came from low-income and middle-income countries, predominantly in eastern Asia, African nations south of the Sahara, and southeastern Asia. The bulk of infection-linked cancer diagnoses in 2024 were made in eastern Asia, making up 42 percent of the global total. The infections linked to those diagnoses were mainly H. pylori and HBV. Getting more people vaccinated for HPV (especially men, who have often not been targeted for HPV vaccines) and HBV should make a huge dent in global cancer rates, but for H. pylori, the answer is not so simple. "So far, there has been little progress in developing H. pylori vaccines or highly effective H. pylori therapies that can minimize ineffective antibiotic exposure, which would be highly impactful for controlling gastric cancer globally," the authors write. We also have no vaccine or any other methods to control the spread of EBV (which infects about 95 percent of adults), though several clinical trials for vaccines are underway. "Although investment in the development of new preventive vaccinations for EBV, H. pylori, and Kaposi's sarcoma [another cancer linked to viruses] is key, many prevention strategies are known to be cost-effective," the authors write. "Unfortunately, such strategies are often underused due to societal, financial, and political barriers, often in the settings that need them most. "Considering the overwhelming economic and social costs of cancer, investment in prevention is crucial." The research was published in The Lancet Oncology.
Author: Jess Cockerill.
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