Preventing infection is one established route to preventing some cancers. That does not mean cancer is generally contagious, or that a common infection makes cancer inevitable. The practical question is which infections can be prevented or managed, and which action is appropriate for a particular person.
A new estimate, with an important date distinction
An International Agency for Research on Cancer analysis published online in The Lancet Oncology on 28 September 2026 estimated that infections accounted for about 2.3 million new cancer cases worldwide in 2024, approximately 12% of the total. The year 2026 is the publication date; the estimate concerns cancer incidence in 2024.
The largest contributors were Helicobacter pylori, human papillomavirus (HPV), hepatitis B, Epstein–Barr virus and hepatitis C. The analysis incorporated additional infection–cancer relationships, including Epstein–Barr virus and some stomach cancers. Its worldwide proportion should not be presented as India’s rate or as an individual’s probability of developing cancer after infection.
Why infection can matter years later
Different organisms act in different ways. Persistent inflammation can damage tissue, some viruses disrupt normal controls on cell growth, and immune suppression can make other cancer-causing infections harder to control. These processes can take years. Many infected people never develop cancer, so a positive infection test needs interpretation rather than panic.
Use the prevention tool that fits
Vaccination: HPV vaccines prevent infection with important cancer-causing HPV types; hepatitis B vaccination reduces the risk of an infection that can lead to liver cancer. Eligibility and dose schedules depend on age, previous vaccination, immune status and local guidance. These vaccines do not treat an existing tumour.
Screening: Cervical screening can find infection or precancerous changes requiring further care. It remains important after HPV vaccination. Screening only delivers its intended benefit when abnormal results are followed by appropriate assessment and, where needed, treatment.
Targeted testing and treatment: A clinician may recommend testing for hepatitis B, hepatitis C or H. pylori based on symptoms, history or exposure. Hepatitis C has effective antiviral treatment but no vaccine. H. pylori can be treated with an appropriate antibiotic regimen; buying antibiotics without testing and advice is not a cancer-prevention plan.
Turn the headline into a useful appointment
Bring any vaccination records and previous infection results. Ask whether you have missed a recommended vaccine, whether cervical screening is due, and whether your history justifies infection testing. If an infection is already diagnosed, clarify the treatment and follow-up plan instead of assuming that vaccination will resolve it.
The research supports better access to proven prevention. It does not justify a universal infection panel, self-prescribed antivirals or antibiotics, or claims that infections explain every cancer. Individual care should follow the evidence for the specific organism and the person being assessed.
References
- IARC: Global burden of cancer attributable to infections in 2024
- WHO: Cervical cancer
- IARC: Questions and answers on infection-attributable cancers
- US National Cancer Institute: Infectious agents
- Rumgay and colleagues: Global burden of cancer attributable to infections in 2024, The Lancet Oncology (28 September 2026)
- IARC Press Release 387: Global burden of cancer attributable to infections in 2024
- WHO: Hepatitis C
- NCI: Common Cancer Myths and Misconceptions
