Answer: World Health Organization
Notes: The World Health Organization (WHO) and International Agency for Research on Cancer (IARC) have classified Hepatitis D virus (HDV) as carcinogenic to humans, alongside Hepatitis B (HBV) and Hepatitis C (HCV). HBV, HCV, and HDV infect over 300 million people globally, causing 1.3 million deaths annually from liver cirrhosis and cancer. HDV affects about 5% of chronic HBV patients, mainly in Asia, Africa, Amazon Basin, and high-risk groups like drug users and haemodialysis patients. Co-infection with HBV raises liver cancer risk 2–6 times; 75% may develop cirrhosis within 15 years. No separate HDV vaccine exists; prevention relies on universal HBV vaccination and testing.
