About one in eight cancer cases are caused by infections with viruses, bacteria, or parasites, a new study finds, suggesting that one of the most effective ways to reduce cancer rates might be to prevent common infections. In a new analysis published September 28 in the journal The Lancet Oncology, researchers mapped the global impact of 12 cancer-causing pathogens. They estimate that infections drove about 2.3 million new cancer cases in 2024, or about 12% of all cancer cases diagnosed that year.
The study highlights that a large fraction of cancer cases could be avoided if these underlying infections were prevented, said Dr. Prashant Mathur, director of India’s National Centre for Disease Informatics and Research, who was not involved in the study.
“When combined with other risk factors such as tobacco use, alcohol consumption, appropriate diet, physical activity, and environmental pollution, it is estimated that about 50 to 60 percent of all cancers in India are avoidable,” Mathur said. Past studies suggest similar figures hold on a global scale.
How Researchers Estimated 2.3 Million Infection-Driven Cancers
In the new study, researchers used the Global Cancer Observatory’s GLOBOCAN database, which combines data from various cancer registries to estimate that about 20 million new cancer cases were diagnosed in 2024.
The team combined that information with other published data examining prevalence of different infections in people with specific cancers. This enabled them to estimate how many cases were attributable to each infection. Their analysis focused on 12 pathogens tied to cancer, including human papillomavirus, or HPV, hepatitis B and C, HIV, and Epstein-Barr virus, or EBV, the virus behind mononucleosis.
Four Pathogens Account for 92% of Infection-Related Cancers
The resulting breakdown revealed that just four pathogens accounted for roughly 92% of cancer cases caused by infections. A bacterium called Helicobacter pylori, which infects the gastrointestinal tract, accounted for 760,000 cases, primarily gastric cancers.
The other three leading cancer triggers were viruses. HPV accounted for 750,000 cases, including cervical, penile, throat, and mouth cancers. The liver-attacking hepatitis B virus was responsible for 360,000 cases, and EBV drove 260,000 cases. EBV is known to increase risk of throat cancers, as well as certain lymphomas and stomach cancers.
The remaining cases were linked to other pathogens including hepatitis C virus and other infectious agents among the 12 studied.
Prevention Gap: HPV Vaccine Coverage Only 31%
The scale of burden contrasts with gaps in prevention. In 2024, just 31% of eligible adolescent girls worldwide received at least one dose of HPV vaccine, well below the 90% target, the World Health Organization reports. The degree of protection provided by vaccine is striking in countries that achieved higher coverage.
Hepatitis B, EBV, and H. pylori: Vaccines and Future Strategies
There is also a highly effective vaccine for hepatitis B, and health officials recommend giving children their first dose as soon as possible after birth. The U.S. Centers for Disease Control and Prevention recently made the decision to stop recommending universal vaccination at birth, which experts say could raise country’s rates of hepatitis B infections and related cancers.
While challenge with HPV and hepatitis B is getting vaccines into widespread use, there is no approved vaccine for EBV yet.
Analysis: Why Prevention Offers Higher Return Than Treatment
1. Concentrated burden: Four pathogens cause 92% of infection cancers, meaning targeted action on H. pylori, HPV, hepatitis B, and EBV could prevent over 2 million cancers annually.
2. Inequity drives burden: 77% of infection-driven cancers occur in low- and middle-income countries where HPV vaccine coverage is lowest, showing access, not biology, drives disparity.
3. Vaccines already exist for biggest wins: HPV and hepatitis B vaccines are highly effective, with countries over 80% coverage seeing cervical cancer starting to disappear. Single-dose HPV could simplify scale-up.
4. Underestimation likely: GLOBOCAN coverage gaps, especially only 2% of Africa, suggest 2.3 million may be conservative.
For Mathur, bottom line is economic: “Studies have clearly demonstrated that return on investment of prevention on cancers is much higher than on its treatment in long run. Preventive aspects must be strengthened for long-term gains.”
Q&A
Q: What percentage of cancers are caused by infections?
A: About 12%, or 1 in 8 cancer cases globally, about 2.3 million of 20 million new cases in 2024, according to Lancet Oncology analysis of 12 pathogens.
Q: Which infections cause most infection-related cancers?
A: Helicobacter pylori 760,000 cases, HPV 750,000 cases, hepatitis B 360,000 cases, and Epstein-Barr virus 260,000 cases, together accounting for 92% of infection-driven cancers.
Q: What is HPV vaccine coverage worldwide?
A: Only 31% of eligible adolescent girls worldwide received at least one HPV dose in 2024, below WHO’s 90% target, with low- and middle-income countries bearing 77% of burden.
Q: Is there a vaccine for EBV?
A: No approved EBV vaccine yet due to viral complexity and latency, but research is accelerating following links to multiple sclerosis and lupus.
FAQ
1. What cancers does HPV cause?
Cervical, penile, throat, mouth, anal, and other cancers, accounting for 750,000 cases in 2024 analysis.
2. What cancers does H. pylori cause?
Primarily gastric cancers, 760,000 cases, the leading infection cause in this study.
3. Can single-dose HPV vaccine work?
Recent trials support single-dose using same vaccines as two-dose series, potentially lowering cost and follow-up needs, according to Dr. Rebecca Perkins.
4. Why are LMICs more affected?
Lower vaccine coverage, limited H. pylori screening and treatment, and limited cancer registry data leading to delayed prevention.
5. Are 50-60% of cancers preventable?
When combining infection prevention with tobacco, alcohol, diet, physical activity, and pollution control, experts estimate 50-60% of cancers in India and similar globally are avoidable.
Disclaimer: This article is for general news and educational purposes. It does not provide medical advice, diagnosis, or vaccination recommendations.
