Serological profile of Hepatitis B virus infection among children under five years of age followed at the mother and Child University Hospital (CHU-ME) of N'Djamena, Chad

Introduction: hepatitis B remains highly endemic in sub-Saharan Africa, where mother-to-child and early childhood horizontal transmission are predominant. This study aimed to determine the prevalence of hepatitis B virus (HBV) infection and describe the serological profile among children under five years of age. Patients and Methods: a descriptive cross-sectional study was conducted from February to July 2024 at the Mother and Child University Hospital in N’Djamena. All children aged 0–59 months attending outpatient consultations or hospitalized were included after parental consent. Capillary blood samples were collected on dried blood spots (DBS) according to WHO recommendations. HBV markers (HBsAg, HBeAg, anti-HBc IgM, and anti-HBs) were analyzed using ELISA. Data analysis was descriptive. Results: a total of 156 children were included. The mean age was 23.3 ± 15.4 months; 42.9% were between 0 and 12 months old. The sex ratio was 1.1. The prevalence of HBsAg was 1.28% (n = 2). One child showed concurrent positivity for HBeAg and anti-HBc IgM, indicating recent infection with active viral replication. No anti-HBs antibodies were detected. Overall vaccination coverage was 56.4%. Conclusion: the low prevalence observed suggests a positive impact of routine childhood vaccination. However, the presence of active HBV infections among infants highlights the need to systematically introduce the hepatitis B birth dose in Chad.