Hepatitis D Reclassified as Carcinogenic, According to WHO

The World Health Organization (WHO) announces the reclassification of hepatitis D as cancerous, emphasizing the urgent need for the elimination of viral hepatitis, according to an official news release. The agency calls on governments to act amid a growing public health crisis.

Hepatitis D blood sample | Image Credit: © Innovative Creation - stock.adobe.com

Viral hepatitis is highly prevalent across the globe, affecting nearly 300 million people and claiming the lives of over 1.3 million each year. Hepatitis is a viral infection that can be acute or chronic, depending on the specific type. For chronic infections, symptom management is the standard of care. However, vaccines can help prevent infection with viral hepatitis.^1,2

"Every 30 seconds, someone dies from a hepatitis-related severe liver disease or liver cancer. Yet we have the tools to stop hepatitis,” Tedros Adhanom Ghebreyesus, MD, WHO Director-General, said in an official news release.¹

There are 5 types of hepatitis viruses. They include³:

• Hepatitis A: Caused by the hepatitis a virus (HAV); contracted from consuming contaminated food or water
• Hepatitis B: Caused by hepatitis B virus (HBV); most common liver infection in the world; often acute but can be chronic
• Hepatitis C: Spreads through shared needles or syringes; more likely to be chronic
• Hepatitis D: Caused by the hepatitis D virus (HDV); most common in those with hepatitis B
• Hepatitis E: Caused by the hepatitis E virus (HEV); typically resolves without treatment; treatment required for pregnant individuals

All types of hepatitis are associated with acute liver infection; however, only hepatitis B, C, and D can lead to chronic infections with a higher risk of liver cirrhosis, failure, or cancer. According to the authors of the study’s findings, hepatitis D is associated with a 2- to 6-fold higher risk of liver cancer compared with hepatitis B.¹

The WHO’s announcement stems from the International Agency for Research on Cancer’s (IARC) reclassification of hepatitis D as carcinogenic, supported by data from a study published in The Lancet Oncology. The study assessed the carcinogenic potential of HDV, human cytomegalovirus (HCMV), and Merkel cell polyomavirus (MCPyV).^4,5

HDV is a single-stranded RNA virus that depends on the presence of the hepatitis B virus for replication and infection. HCMV, a member of the beta-herpesvirus family, is commonly transmitted via bodily fluids and can be passed from mother to fetus during pregnancy. MCPyV is a widely circulating virus typically acquired during early childhood through direct contact and is known to persist on the skin as part of the normal virome.⁵

The WHO’s classification of hepatitis D as carcinogenic marks a pivotal moment in the global fight against viral hepatitis. With mounting evidence linking HDV to significantly elevated cancer risk, health leaders are urging swift policy action, expanded access to hepatitis B vaccination, and stronger surveillance systems. As the burden of viral hepatitis continues to grow—despite the availability of effective prevention tools—experts stress that eliminating hepatitis is not only possible but also essential to reducing liver cancer worldwide.

REFERENCES

1. WHO urges action on hepatitis, announcing hepatitis D as carcinogenic. WHO. July 28, 2025. Accessed August 4, 2025. https://www.who.int/news/item/28-07-2025-who-urges-action-on-hepatitis-announcing-hepatitis-d-as-carcinogenic

2. Global viral hepatitis. CDC. July 25, 2025. Accessed August 4, 2025. https://www.cdc.gov/hepatitis/global/index.html

3. What is viral hepatitis? Cleveland Clinic. March 27, 2025. Accessed August 4, 2025. https://my.clevelandclinic.org/health/diseases/4245-hepatitis-viral-hepatitis-a-b--c#overview

4. Karagas M, Kaldor J, Michaelis M, et al. Carcinogenicity of hepatitis D virus, human cytomegalovirus, and Merkel cell polyomavirus. The Lancet Oncology. June 27, 2025. doi: 10.1016/S1470-2045(25)00403-6

5. IARC Monographs evaluation of the carcinogenicity of hepatitis D virus, human cytomegalovirus, and Merkel cell polyomavirus. International Agency for Research on Cancer. June 27, 2025. Accessed August 4, 2025. https://www.iarc.who.int/news-events/iarc-monographs-evaluation-of-the-carcinogenicity-of-hepatitis-d-virus-human-cytomegalovirus-and-merkel-cell-polyomavirus/