Around 12% of the world’s total cancer cases in 2024 were likely caused by an infection, according to new research from the World Health Organisation (WHO).

The study, published in The Lancet Oncology, analysed the frequency and causes of different cancers , specifically examining the role of infections.

It linked 2.3 million new cancer cases to an infection. Most were caused by just five pathogens: Helicobacter pylori (4%), human papillomavirus, or HPV (4%), hepatitis B (2%), Epstein-Barr virus (1%) and hepatitis C (under 1%). These infections can cause more than 20 different types of cancer, including stomach, liver, blood and cervical cancers.

So, how can an infection cause cancer? And does this mean these cancers are preventable?

Did we already know about this link?

Some of the study authors have been researching this field for around thirty years.…