An estimated one in eight cancer cases diagnosed worldwide in 2024, or roughly 2.3 million people, were directly caused by infections. That is according to a study published on September 28, 2026, in The Lancet Oncology.
One in Eight Global Cancer Diagnoses Linked to Preventable Infections
Researchers found that approximately 12 percent of global cancer diagnoses can be attributed to infectious agents that remain largely preventable or treatable through targeted public health measures.
Two Pathogens Account for 1.5 Million Cases Worldwide
The new analysis updates prior research conducted in 2018, detailing how specific viral, bacterial, and parasitic agents establish chronic inflammation or disrupt host cell DNA to trigger oncogenesis.
The study reveals that just two pathogens—Helicobacter pylori bacteria and the human papillomavirus (HPV)—accounted for more than 1.5 million cancer cases combined worldwide in 2024.
Hepatitis B infections accounted for an estimated 360,000 cancer cases, while the Epstein-Barr virus was linked to 260,000 cases. Hepatitis C contributed a smaller proportion, remaining under 1 percent of total diagnoses. Together, these infectious agents drive more than 20 distinct malignancies, including stomach, liver, cervical, throat, and blood cancers.
Targeted Screening and Antibiotics Offer Direct Solutions
Gary Clifford, an epidemiologist at the International Agency for Research on Cancer and senior author of the study, emphasizes that these figures represent highly actionable public health targets. Testing, antibiotic regimens, and widespread vaccination programs can neutralize these threats before cellular damage occurs.
Anna Giuliano, founding director of the Center for Immunization and Infection Research in Cancer at the Moffitt Cancer Center, notes that patients can be screened and treated for hepatitis C, vaccinated against hepatitis B to prevent liver cancer, and treated with antibiotics to reduce the risk of cancer in people with H. pylori infection. Furthermore, the HPV vaccine protects against six different cancers, including cervical, throat, and anal cancers.
Two Decades of HPV Vaccines Show Tangible Progress
Data from the 20 years since the HPV vaccine was first introduced in the United States in 2006 demonstrate tangible progress.
Cervical cancer rates have dropped by more than 50 percent in some states among women aged 20 to 31, who were the first group eligible to receive the vaccine as preteens. Similar benefits have been documented globally.
Nancy Lee, an oncologist at Memorial Sloan Kettering Cancer Center, highlights that HPV vaccination remains critical for curbing infections, particularly as HPV-related throat cancer becomes a growing clinical concern in the United States.
Sub-Saharan Africa Faces Disproportionate Health Burdens
The research highlights distinct geographic variations in where infection-linked cancers occur. Sub-Saharan Africa bears a higher rate of these cases, driven largely by disparities in healthcare investment, such as limited access to cervical cancer screening programs compared to countries like the United States.
Health officials indicate that mapping these infection-linked cancer burdens allows international agencies to direct preventative resources where vulnerabilities are highest.
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