Epidemiology of HDV Infection in Europe

Epidemiology of HDV Infection in Europe

Lecture Summary | Prof. Heiner Wedemeyer

1. Main Clinical Topics Discussed

• Global and European epidemiology of Hepatitis Delta Virus (HDV) infection
• Challenges in estimating true HDV prevalence
• Impact of migration on HDV epidemiology in Europe
• Natural history of HDV infection and liver disease progression
• Screening strategies and diagnostic limitations
• Treatment landscape and monitoring needs for HDV patients

2. Key Learning Points, Guidelines, and Recommendations

• HDV as an orphan disease in Europe: HDV has historically been underrecognized and underdiagnosed across European healthcare systems
• Systematic screening is essential: Given the availability of new treatments, identification of HDV-positive patients is now a clinical priority
• Point-of-care testing for HDV has not yet been widely established and requires further commercial development and promotion
• Migration patterns significantly influence HDV epidemiology in Central and Western Europe, particularly through populations arriving from Africa, Eastern Europe, and other high-endemic regions
• Distinction between population-based studies and hepatology clinic-based studies is critical when interpreting prevalence data, as clinic populations carry significant selection bias
• Effective monitoring strategies are urgently needed to track HDV burden over time

3. Specific Clinical Data, Statistics, and Study Results Cited

• Global HDV burden: A systematic review and meta-analysis published in the *Journal of Hepatology* estimates approximately 12 million HDV infections worldwide (some earlier estimates suggested up to 70 million)
• European patient estimates: Approximately 250,000 patients in Europe are estimated to be living with HDV infection
• High-prevalence regions in Europe include:

- Romania

- Albania

- Other Eastern European countries

• Romania demonstrates notably higher HDV prevalence compared to other European countries, attributed to historical risk factors including healthcare-associated transmission, risk behaviors, and older patient cohorts
• A systematic review and meta-analysis by Alexander Stockdale and colleagues, published in September in a peer-reviewed journal, distinguished between:

- General population-based studies

- Studies performed in hepatology clinic settings

- Findings confirmed significant variation across European regions (Benelux, Scandinavia, Eastern Europe)

• A recent paper published in *Hepatology* discussed HDV in the context of active HBsAg-positive patients, providing updated natural history and population-based data
• Age distribution among HDV patients in Europe is shifting — the existing cohort includes older patients, while new cases increasingly reflect immigration patterns

4. Practical Takeaways for Clinicians

• Test all HBsAg-positive patients for HDV — reflex testing for delta antigen/anti-HDV antibody should be standard practice given the implications for liver disease severity and treatment eligibility
• Do not rely solely on historical prevalence data — figures vary substantially depending on whether they derive from general population surveys or clinical cohort studies
• Account for immigration background when assessing HDV risk in patients; individuals from Romania, Albania, Africa, and other high-endemic regions carry elevated risk
• HDV accelerates liver disease progression — patients with HDV superinfection or coinfection are at significantly higher risk of cirrhosis and hepatocellular carcinoma compared to HBV monoinfection
• New treatments are now available — timely identification of HDV-positive patients is essential so they can benefit from emerging therapeutic options within a short treatment window
• Advocate for systematic HDV screening programs at the national and European level, particularly in countries with high immigration from endemic regions
• Support development and validation of point-of-care HDV diagnostics to facilitate screening in lower-resource or primary care settings

*Note: This summary was generated from an automatically transcribed lecture recording. Some data points may reflect transcription artifacts; verification against the original published sources is recommended for clinical or academic use.*