A study conducted by researchers from the International Agency for Research on Cancer indicates that one in eight cancers worldwide may be linked to infections, many of which could be prevented through vaccinations. The research estimates that of the 19.2 million new cancer cases projected for 2024, approximately 2.3 million are connected to infections. The majority of these cases are associated with five specific infections: Helicobacter pylori (H. pylori), human papillomavirus (HPV), hepatitis B, hepatitis C, and Epstein-Barr virus (EBV).
Low- and middle-income countries bear the largest burden, accounting for about 77% of all infection-related cancer cases. Eastern Asia has the highest number, with 990,000 cancer cases linked to infections, primarily driven by H. pylori and hepatitis B. The findings, published in The Lancet Oncology, emphasize the need for infection control to reduce cancer rates. The authors note that while investment in new preventive vaccinations is important, many existing strategies are cost-effective but underutilized due to societal, financial, and political barriers.
The report highlights the need to improve the uptake of the HPV vaccine, promote safe injection practices, increase access to condoms and HIV prevention drugs, and identify and treat early signs of cervical and anal cancer. In Western Europe, HPV is linked to 24,000 cancer cases in 2024, making it the leading infection-related cause of cancer in the region. HPV is a common virus that can lead to various cancers, including cervical cancer, and vaccination and screening are central to the World Health Organization's strategy to eliminate cervical cancer.
The study also found that H. pylori is the largest infection-related cause of cancer globally, responsible for about 760,000 cases in 2024, primarily stomach cancers. Research suggests H. pylori may account for up to one in five bowel cancer cases, with exposure to the bacteria increasing the risk of colorectal cancers by 60%. Despite the potential impact of vaccines against H. pylori, progress in their development has been slow.
The Epstein-Barr virus, which infects around 95% of UK adults at some point, is now the fourth-largest cause of cancer globally. The researchers caution that while infections contribute to cancer risk, other factors such as genetics, overall health, and diet also play significant roles. They advocate for EBV to be a target for prevention, noting that several clinical trials for EBV vaccines are currently underway.
Hepatitis B and C together account for about one-third of all infection-related cancers, primarily liver cancer. Effective treatments exist for hepatitis B, and hepatitis C can often be cured. The NHS recommends hepatitis B vaccination for all babies and high-risk individuals. There is currently no approved vaccine for hepatitis C, and prevention relies on testing and reducing exposure to infected blood. The findings come amid concerns about rising rates of early-onset cancer, particularly in women, prompting the government to develop a national cancer plan aimed at improving lifestyles and early diagnosis.