A major international analysis has connected infections to about one in eight new cancer cases worldwide in 2024. That amounted to 2.3 million cases, according to findings from the International Agency for Research on Cancer.

Conducted in France, the study analyzed cancer data from 2024. The findings were published in The Lancet Oncology on Sept. 28.

Researchers identified 12 infections linked to human cancer cases. The list included Helicobacter pylori, known as H. pylori, human papillomavirus, hepatitis B virus, hepatitis C virus and HIV.

The analysis also identified Epstein Barr virus, Kaposi sarcoma-associated herpesvirus, Schistosoma haematobium, HTLV-1, Opisthorchis viverrini, Clonorchis sinensis and Merkel cell polyomavirus. Five infections contributed to nearly all the global cases.

Study coauthor Dr. Harriet Rumgay, a scientist in the Cancer Surveillance Branch at IARC, said controlling infections could play a major role in reducing cancer worldwide.

“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,” Rumgay said in a press release.

Researchers said many of these cancers could have been prevented through vaccination, treatment or screening. Their findings point to opportunities for addressing infections before they contribute to cancer.

Dr. Joshua Cohen, medical director of the Gynecologic Cancer Program of City of Hope Orange County in Irvine, California, was not involved in the research. He emphasized that infections represent only one part of the overall cancer picture.

“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.

Cohen 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 on its own.

“We don't know why some patients' immune systems allow them to clear the HPV infection and some don't,” Cohen said.

Gastric cancer, although less common in the U.S., is another cancer associated with infection, Cohen noted. It has been linked to H. pylori, an infection found in the stomach.

“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,” he said.

People who have peptic ulcer disease or significant epigastric pain should speak with a gastroenterologist about screening and treatment for H. pylori, Cohen advised. Epigastric pain involves pain or discomfort in the upper middle portion of the abdomen.

Cohen said other warning signs can include acid reflux, abnormal vaginal bleeding or pain with swallowing. Those symptoms could be connected to medical conditions that may be associated with certain infections or cancer.

Cohen also urged people to consider how they can prevent infections and protect their families. For those who already have an infection, he recommended discussing ways to reduce the risk of subsequently developing cancer.

Americans have access to HPV vaccination, which can help prevent many infections, Cohen emphasized. He advised people younger than 45 who have not received an HPV vaccination to consider getting vaccinated based on available safety data.

“That will cover, at least in the U.S., most risks regarding oropharyngeal cancers, vaginal cancers, cervical cancers, penile cancers and anal cancers,” he said.

Having one of the infections identified by researchers does not mean cancer is inevitable. “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,” Cohen said.

The study had several limitations because it relied on population estimates rather than following individual patients over time. Its results therefore depended on the quality of available cancer data in each country.

The analysis included only infections already proven to cause cancer, meaning the total impact could be underestimated. Cohen said seeking treatment remains important when infections have been associated with particular cancers.

“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,” Cohen added.