October 5, 2026, 6:03 pm | Read time: 4 minutes
When thinking about cancer prevention, most people first consider a healthy diet, exercise, and avoiding cigarettes. Indeed, these factors are considered important levers for health. However, many people overlook one risk: certain infections.
Researchers have now calculated that around 2.3 million cancer cases worldwide in 2024 were due to viruses, bacteria, or parasites–equivalent to about one in eight new cases.1
Millions of Cancer Cases Due to Infections
Researchers from the International Agency for Research on Cancer (IARC) have now examined the share of infectious diseases in the global cancer burden. Their analysis, published in the journal “The Lancet Oncology,” comes to a clear conclusion: Of the approximately 20 million newly diagnosed cancer cases in 2024, about 2.3 million were associated with viruses, bacteria, or parasites. Thus, roughly one in eight cancer cases was infection-related.
According to the scientists, the significance of such pathogens in cancer development is often underestimated. At the same time, the data show that prevention and early treatment could reduce the risk for many affected individuals.
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Five Pathogens Cause Cancer
The highest rates of infection-related cancers were found in countries with low and middle incomes. Therefore, the global results cannot be directly applied to Germany. Here, extensive prevention programs, vaccinations, and medical treatments are available.
The majority of infection-related cancers worldwide can be traced back to five pathogens. An infection does not automatically lead to cancer. Usually, other factors such as the immune system, genetic predisposition, or lifestyle play a role.
Helicobacter pylori: Risk Factor for Stomach Cancer
With around 760,000 cancer cases worldwide, the bacterium Helicobacter pylori was the most significant infectious trigger in 2024. It is considered the leading cause of stomach cancer. Estimates suggest that about 15 to 30 percent of people in Germany become infected with the bacterium during their lifetime.
HPV: Common Infection with Consequences
Human papillomaviruses (HPV) were linked to about 750,000 cancer cases worldwide. The pathogens cause more than 90 percent of all cases of cervical cancer. They also increase the risk of tumors in the oral-pharyngeal area, anus, and penis. HPV is one of the most common sexually transmitted infections. Experts believe that the majority of sexually active people become infected at least once in their lifetime.
Hepatitis B and Hepatitis C Attack the Liver
Around 360,000 cancer cases worldwide were attributed to Hepatitis B in 2024. The liver is particularly affected. According to the Robert Koch Institute, the prevalence in Germany is less than one percent of the population.2 Hepatitis C also plays an important role. Researchers attributed about 160,000 cancer cases worldwide to the virus. As with Hepatitis B, these are predominantly liver cancers.
Epstein-Barr Virus is Widespread
The Epstein-Barr virus (EBV) was associated with about 260,000 cancer cases worldwide. These include certain lymphomas and stomach cancer. More than 90 percent of all adults carry the virus. Often, the infection occurs unnoticed, sometimes causing what is known as infectious mononucleosis.
These Measures Can Reduce Cancer Risk
Experts see prevention and vaccinations as the most important ways to protect against the most dangerous pathogens. Study author Harriet Rumgay from the International Agency for Research on Cancer emphasizes the importance of such measures: “The results show how crucial the prevention and treatment of infections are for cancer prevention.”
HPV Vaccination
Statutory health insurance covers the cost of the HPV vaccination for girls and boys between the ages of nine and 14. Catch-up vaccinations are generally possible until the age of 18. The vaccination protects against the HPV types responsible for most cases of cervical cancer and other cancers in the genital and oral-pharyngeal areas.
Hepatitis B Vaccination
The Hepatitis B vaccination is one of the standard vaccinations in childhood in Germany. It can protect against chronic infections that increase the risk of liver cancer.
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Regular Check-Ups
Gynecological early detection examinations help identify cell changes before they develop into cervical cancer.
Detect Infections Early
Diseases caused by Helicobacter pylori, Hepatitis B, Hepatitis C, or HIV can often be diagnosed and treated early. This can significantly reduce the risk of later cancer consequences.