Infections Linked to 2.3 Million New Cancer Cases Worldwide

About 1 in 8 new cancer cases worldwide in 2024 was attributed to an infection, according to a new global analysis published in Lancet Oncology.

Infections were responsible for 2.3 million, or 12%, of all new cancer diagnoses. Five infections accounted for most of the infection-attributable cancer burden: helicobacter pylori (H. Pylori), human papillomavirus (HPV), hepatitis B, Epstein-Barr virus and hepatitis C.

H. pylori was linked to the highest number of cases — around 760,000 — and mainly causes stomach cancer. HPV was linked to about 750,000 cases. The analysis found 100% of cervical cancer cases are caused by HPV, while the virus also contributes to cancer of the anus, penis, vulva, vagina and oropharynx.

An estimated 360,000 cases were linked to hepatitis B infection, 260,000 to the Epstein-Barr virus and 160,000 cases to hepatitis C.

Proven Interventions

The new estimates update older research conducted in 2018.

“I think it is really important that these updates happen to remind everyone that there are infectious agents that cause cancer and that there is something we can do to prevent and cure these cancers,” said Anna Giuliano, PhD, an epidemiologist and founding director of the Center for Immunization and Infection Research in Cancer at Moffitt Cancer Center. “This publication highlights the need to implement and broadly disseminate proven interventions to prevent, screen and cure some of these cancers.”

I think it is really important that these updates happen to remind everyone that there are infectious agents that cause cancer and that there is something we can do to prevent and cure these cancers.

Anna Giuliano, PhD

For example, she says, people can be screened and treated for hepatitis C, effectively preventing the virus from progressing to liver cancer. Similarly, vaccination against hepatitis B prevents liver cancer. H. pylori infections can be treated with antibiotics, and the HPV vaccine can prevent six different types of cancer in men and women.

“It’s been 20 years since the first licensure of the HPV vaccine. There is worldwide evidence that the vaccine does what it intended to do: prevent cancers caused by HPV,” Giuliano said.

Furthering Research

There were geographic differences in where cancers caused by infections occurred. The cancer burden was disproportionately concentrated in low- and middle-income countries, which accounted for 77% of cancer cases linked to infection. Eastern Asia had about 990,000, or 42% of the global total, while the proportion of cancers linked to infections was particularly high in sub-Saharan Africa.

The analysis was the first time HIV was included in a review of infections that cause cancer. The researchers also highlighted the Epstein-Barr virus as an increasingly important contributor to the global cancer burden. It is now the fourth-leading infectious cause of cancer and has been linked to additional cancer types such as stomach cancer and lymphomas, in additional to nasopharyngeal cancer.

2.3 million new cancer cases worldwide in 2024 – about 12% of all new cancer cases – were caused by infections.
Infection control can play a major role in reducing the global cancer burden.https://t.co/Whnw6tXqra pic.twitter.com/3FIt49DNjB

— IARC (@IARCWHO) September 30, 2026

Overall, the study emphasizes the role preventable and treatable infections play in cancer and identifies vaccination, infection control and early detection as important components of cancer prevention.

“When cancer researchers first started studying causes of cancer, the methods and tools that are needed to advance this field of research were not available. But now we have robust tools to allow us to identify infectious causes of cancers and the percentage of cancers caused by these agents,” Giuliano said. “We need to continue to study infection as a cause of cancer as we also have the tools to develop efficacious interventions to prevent and cure these infections, ultimately reducing the burden of cancer.”