Hepatitis D virus labelled cancer-causing agent: All you need to know

The new classification highlights major gaps in testing and treatment, and reinforces the need for better data, affordable medicines, and stigma-free care

The World Health Organization (WHO) and the International Agency for Research on Cancer (IARC) has formally reclassified the Hepatitis D virus (HDV) as carcinogenic to humans, placing it alongside Hepatitis B and C as known causes of liver cancer. This reclassification, supported by data from a study published in The Lancet Oncology, marks a critical step in global efforts to raise awareness, improve screening, and expand access to new treatments for hepatitis D. 

What's the latest 

 

According to WHO, Hepatitis B, C, and D together affect over 300 million people globally, contributing to around 1.3 million deaths each year, primarily from liver cirrhosis and cancer. Current estimates suggest HDV infects nearly 5 per cent of people with chronic HBV (hepatitis B virus), equating to around 12 million individuals worldwide.

 

 

High-risk populations include those in regions with elevated HBV prevalence, such as parts of Asia, Africa and the Amazon Basin as well as people who inject drugs and recipients of haemodialysis.  

 

Why is hepatitis D considered dangerous?

 

HDV can only infect individuals who already carry HBV. HDV essentially hijacks HBV to replicate and cannot cause infection on its own.

 

Co-infection or superinfection with HBV dramatically worsens outcomes as HDV raises the risk of liver cancer by two to six times compared with HBV alone, said the study. 

 

Up to 75 per cent of chronic HDV patients were likely to develop liver cirrhosis within 15 years, whereas individuals with only HBV were about 50 per cent less likely to develop liver cancer.

 

The virus spreads through infected blood, unprotected sex, unsafe injections, or occasionally passes from mother to child during birth.

 

Symptoms usually include fatigue, nausea, abdominal discomfort, dark urine or yellowing of the skin. Many people ignore these signs or confuse them with other illnesses.

 

Treatment landscape

 

While HBV can be controlled with life-long antivirals, options for HDV are more limited but evolving. The antiviral bulevirtide has emerged in Europe as an approved therapy offering improved outcomes alongside pegylated interferon in some cases. 

 

There is no separate vaccine for hepatitis D. The only way to stop it is by getting the hepatitis B vaccine, which protects against both viruses.

 

According to WHO, as of 2025, 129 countries have adopted policies for hepatitis B testing among pregnant women, up from 106 reported in 2024. Meanwhile 147 countries have introduced the hepatitis B birth dose vaccination, an increase from 138 in 2022.

 

However, the 2024 Global Hepatitis Report highlights major gaps in testing and treatment. By 2022, only 13 per cent of people with hepatitis B and 36 per cent with hepatitis C were diagnosed, while treatment rates were just 3 per cent and 20 per cent, respectively. This was well below the 2025 targets of 60 per cent diagnosed and 50 per cent treated. 

 

The integration of hepatitis services remains uneven, with only 80 countries incorporating hepatitis services into primary health care so far.

 

What this means for public health

 

The designation of HDV as Group 1 carcinogen by IARC is expected to mobilise funding, enhance surveillance and improve global awareness about its risks.

  Experts urge governments and health systems to 

• scale up HBV vaccination coverage
• ensure universal testing in HBV-positive individuals
• expand access to novel HDV therapies

 

To meet WHO’s 2030 goals and potentially save 2.8 million lives while preventing 9.8 million new infections, countries must invest in domestic healthcare systems, ensure affordable medicines, improve data systems, and address stigmas.    For more health updates, follow #HealthWithBS