A major global analysis has linked infections to about one in eight new cancer cases diagnosed worldwide in 2024. That amounts to 2.3 million cases, according to researchers from the International Agency for Research on Cancer.

The study was conducted in France and examined cancer data from 2024. Its findings were published in The Lancet Oncology on Sept. 28.

Researchers identified 12 infections associated with human cancers. They included Helicobacter pylori, known as H. pylori, human papillomavirus, hepatitis B virus, hepatitis C virus, Epstein Barr virus, HIV and several other viruses and parasites.

Other infections identified in the analysis included Kaposi sarcoma-associated herpesvirus, Schistosoma haematobium, HTLV-1, Opisthorchis viverrini, Clonorchis sinensis and Merkel cell polyomavirus. Five of the infections contributed to nearly all the cases included in the worldwide estimate.

“The findings underscore the major role that infection control can play in reducing the global cancer burden,” study co-author Dr. Harriet Rumgay, a scientist in the Cancer Surveillance Branch at IARC, said in a press release.

“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. Their analysis also came with several acknowledged limitations.

Because the researchers used population level estimates instead of following individual patients over time, the results depended on the quality of cancer data available in each country. The analysis also included only infections already proven to cause cancer, meaning the total impact could be underestimated.

Dr. Joshua Cohen, medical director of the Gynecologic Cancer Program of City of Hope Orange County in Irvine, California, was not involved in the study. He emphasized that exposure to an infection does not mean cancer is inevitable.

“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,” Cohen told Fox News Digital. “However, most cancers are not caused by infection.”

HPV is among the most common drivers of cancers arising along the rectum, vagina or cervix, as well as the oropharynx at the back of the throat, according to Cohen. “80% of the population has been exposed to certain types of HPV strains,” he said. “About 40,000 people in the U.S. are diagnosed with these cancers each year.”

For most people exposed to HPV, the body clears the virus without intervention, Cohen said. “We don't know why some patients' immune systems allow them to clear the HPV infection and some don't.”

H. pylori, an infection found in the stomach, is linked to gastric cancer, Cohen noted. Although gastric cancer is less common in the U.S., he said the infection is more prevalent in other parts of the world.

“We don't screen everybody for H. pylori in the U.S. — it's more common in other parts of the world, like Southeast Asia.” Cohen advised people with peptic ulcer disease or significant epigastric pain to speak with a gastroenterologist about screening and treatment.

Cohen said people can take steps to lower their risk of cancers associated with infections. “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.

He also pointed to HPV vaccination as an available preventive measure for Americans. “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,” Cohen said.

“That will cover, at least in the U.S., most risks regarding oropharyngeal cancers, vaginal cancers, cervical cancers, penile cancers and anal cancers.” Even so, Cohen stressed that most people with HPV, H. pylori, hepatitis B or hepatitis C will not develop cancer.

Symptoms including epigastric pain, acid reflux, abnormal vaginal bleeding or pain with swallowing may be connected 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.