Published: 11:18 PM, 02 October 2026
Everyday infections tied to one in eight cancer cases worldwide: Study
About one in eight new cancer cases worldwide, or 2.3 million cases, in 2024 have been linked to infections, according to a new analysis by the International Agency for Research on Cancer (IARC).
The researchers identified 12 infections associated with human cancers, including Helicobacter pylori (H pylori), human papillomavirus (HPV), hepatitis B virus (HBV), hepatitis C virus (HCV), Epstein-Barr virus (EBV) and Kaposi sarcoma-associated herpesvirus, Fox News reports.
The list also includes Schistosoma haematobium, HTLV-1, Opisthorchis viverrini, Clonorchis sinensis, Merkel cell polyomavirus and HIV.
Five of these infections accounted for nearly all the cases:
o H pylori: about 760,000 cases
o HPV: about 750,000 cases
o HBV: about 360,000 cases
o EBV: about 260,000 cases
o HCV: about 160,000 cases
"The findings underscore the major role that infection control can play in reducing the global cancer burden," study co-author Harriet Rumgay, a scientist in the Cancer Surveillance Branch at IARC, said in a media statement.
"Despite progress in vaccination and screening, infection-related cancers remain a major global challenge, with the burden falling disproportionately on populations in low- and middle-income countries."
The researchers said many of these cancers could have been prevented through vaccination, treatment or screening.
The study, conducted in France, analysed cancer data from 2024. Its findings were published in The Lancet Oncology on Sept 28.
Study Limitations
The study had several limitations, according to the researchers.
As it used population-level estimates rather than tracking individual patients over time, the findings depended on the quality of available cancer data in each country.
It also included only infections already proven to cause cancer, meaning the overall impact could have been underestimated.
"We know that there are certain infections that we are exposed to over our lifetime that may result in an increased risk of certain cancers," Joshua Cohen, medical director of the Gynecologic Cancer Program of City of Hope Orange County in Irvine, California, told Fox News Digital.
"However, most cancers are not caused by infection."
HPV is one of the most common drivers of cancers affecting the rectum, vagina or cervix, as well as the oropharynx, or the back of the throat, said Cohen, who was not involved in the study.
"Eighty percent of the population has been exposed to certain types of HPV strains," he said. "About 40,000 people in the US are diagnosed with these cancers each year."
For most people exposed to HPV, the body clears the virus on its own, Cohen said.
"We don't know why some patients' immune systems allow them to clear the HPV infection and some don't."
Another common cancer, although less so in the US, is gastric cancer, which is linked to H pylori, an infection in the stomach, he said.
"We don't screen everybody for H pylori in the US - it is more common in other parts of the world, like Southeast Asia."
However, people with peptic ulcer disease or significant epigastric pain should talk to a gastroenterologist about being screened and treated for H pylori, Cohen advised.
Prevention Strategies
There are steps people can take to reduce their risk of infection-related cancers, according to Cohen.
"As a patient, the most important thing is to think about your health, what you can do to prevent yourself from developing these infections or your family," he said.
"And if you do have one of these infections, what can you do to reduce your risk of developing a subsequent cancer?"
Cohen said Americans have access to an HPV vaccine that can help prevent many of these infections.
"If you're under the age of 45 and you've not had an HPV vaccination, there is various good safety data that you should get vaccinated," he said. "That will cover, at least in the US, most risks regarding oropharyngeal cancers, vaginal cancers, cervical cancers, penile cancers and anal cancers."
The doctor reiterated that having one of the listed infections does not necessarily mean someone will develop cancer.
"The vast majority of patients who have an HPV infection or H pylori, or even hepatitis B or C, are not going to develop cancer," he said.
But because these infections have been associated with certain cancers, it is important to seek treatment for them.
Symptoms such as epigastric pain, or pain or discomfort in the upper middle part of the abdomen, acid reflux, abnormal vaginal bleeding or pain with swallowing could be related to medical conditions associated with certain infections or cancer, Cohen warned.
"There are steps we can take as doctors to keep you safe and hopefully reduce the risk of developing cancer for those that have had an infection," he added.
