# Burden and Clinical Impact of Hepatitis D Virus Co-Infection Among HBsAg-Positive Patients in Mauritania

## TL;DR

Hepatitis D virus co-infection is common in Mauritania and significantly worsens liver disease outcomes in hepatitis B patients.

## Contribution

This study confirms Mauritania as a hyper-endemic area for HDV and highlights its severe clinical impact.

## Key findings

- HDV antibodies were detected in 31.9% of HBsAg-positive patients.
- HDV co-infection was strongly associated with cirrhosis and hepatocellular carcinoma.
- HDV co-infection is the main driver of severe liver disease despite low HBV DNA levels.

## Abstract

Background: Hepatitis B virus (HBV) infection remains highly endemic in sub-Saharan Africa, where hepatitis delta virus (HDV) co-infection substantially worsens liver disease outcomes. Mauritania has long been suspected to be a high-burden setting for HBV-HDV co-infection, yet contemporary data describing its clinical and virological impact remain limited. Methods: We conducted a hospital-based cross-sectional study at the National Institute of Hepato-Virology (INHV) in Nouakchott, including 401 HBsAg-positive patients. Demographic, clinical, biological, and virological data were collected. HDV serology and RNA testing were performed when available. Liver disease severity, including cirrhosis and hepatocellular carcinoma (HCC), was assessed using clinical, biological, and imaging criteria. Results: HDV antibodies were detected in 31.9% of HBsAg-positive patients, confirming Mauritania as a hyper-endemic area for HDV. HDV co-infection was strongly associated with advanced liver disease, with HDV antibodies present in 86.4% of cirrhotic patients and 82.4% of those with HCC. Patients with HDV infection frequently exhibited suppressed HBV DNA levels, reflecting viral interference. A substantial proportion of patients presented with decompensated cirrhosis or HCC at diagnosis, and nearly 70% were treatment-naïve. Overall, HDV co-infection emerged as the principal driver of severe liver disease in this cohort. Conclusions: HBV/HDV co-infection is highly prevalent in Mauritania and is associated with a wide clinical spectrum ranging from asymptomatic infection to decompensated cirrhosis and hepatocellular carcinoma. HDV co-infection is the principal driver of severe liver disease, often occurring despite low or undetectable HBV DNA levels. Systematic HDV screening among all HBsAg-positive individuals is urgently needed to improve risk stratification, guide therapeutic decisions, and reduce liver-related morbidity and mortality.