Japan's decades-long campaign against hepatitis B and C could become one of the world's strongest examples of how sustained screening, vaccination and timely treatment can dramatically reduce life-threatening viral infections, according to a new study that projects hepatitis C could be close to elimination in the country by 2050.

Researchers from Hiroshima University's Graduate School of Biomedical and Health Sciences analysed two decades of national data and found that the burdens of both hepatitis B viruses (HBVs) and hepatitis C viruses (HCVs) had fallen much faster than previously expected. Their findings, published as an early view article in Hepatology Research in March 2026, suggest that Japan's public health strategy may provide a practical roadmap for countries still struggling with large numbers of undiagnosed infections.

Hepatitis B and hepatitis C attack the liver, an organ that removes toxins and helps digest food. Many infected people develop no symptoms for years, allowing the viruses to silently damage the liver. If left untreated, long-term infection can lead to cirrhosis, a condition in which healthy liver tissue is replaced by scar tissue, increasing the risk of liver failure and liver cancer.

HBV spreads through infected blood and unprotected sexual contact, as well as from mother to child during birth, while HCV is transmitted mainly through blood-to-blood contact. The World Health Organization has identified viral hepatitis as one of the leading infectious causes of death globally, making early diagnosis and treatment central to its elimination strategy.

To estimate future trends, the Hiroshima team used a Markov model—a mathematical method that predicts how diseases change over time by tracking people as they move through different stages of illness and care. Researchers classified individuals into six groups, including undiagnosed carriers, newly infected people, patients receiving treatment, those diagnosed but not linked to medical care, cured patients, and those who had died.

The study found that chronic hepatitis B and C infections declined from about three million cases in 2000 to between 1.1 million and 1.4 million by 2020, outperforming earlier forecasts. The sharpest decline occurred among people who were unknowingly carrying the viruses, reflecting years of expanded screening and improved access to healthcare.

Using current trends, the researchers estimate that hepatitis B infections could fall to around 200,000 by 2050 from nearly one million cases in 2020. Hepatitis C is projected to decline even more dramatically to fewer than 20,000 cases.

"In addition, the number of undiagnosed individuals has fallen to only tens of thousands, and HCV infections are projected to decrease to fewer than 20,000 by 2050. This represents a remarkable transition from a widespread chronic infection to a potentially near-eliminated disease," said Tomoyuki Akita, lecturer at Hiroshima University's Graduate School of Biomedical and Health Sciences.

The researchers credited Japan's success to ongoing efforts in screening blood donors, regularly testing pregnant women, providing hepatitis B vaccinations, offering government-funded treatments, and making antiviral medicines more accessible that can control HBV and cure most HCV infections. These measures have steadily reduced new infections while ensuring that more patients receive care before irreversible liver damage develops.

The study also acknowledged limitations. Some rare transmission routes were excluded, and several model estimates relied on previous research because nationwide linked patient data were unavailable. Future changes in healthcare access or treatment patterns could also influence long-term outcomes.

Even so, the findings reinforce a broader scientific message: eliminating hepatitis requires persistence rather than quick fixes. Japan's experience shows that sustained public health policies, combined with early diagnosis and affordable treatment, can transform a once-common chronic infection into a disease that edges closer to history. For countries still carrying a heavy hepatitis burden, the lesson is clear—the path to elimination begins long before symptoms appear.