Two-Decade Evaluation of Pediatric Hepatitis B Immunization: Shifting Immune Kinetics and Metabolic/Clinical Predictors of Vaccine Non-Response

Abstract

Background: Hepatitis B remains a major public health threat associated with risks of cirrhosis and hepatocellular carcinoma. In Algeria, a country of intermediate endemicity (prevalence of 2% to 8%), vaccination was integrated into the Expanded Program on Immunization (EPI) in 2000. This study evaluates the effectiveness of this national strategy by measuring the post-vaccination immune response within a pediatric cohort in the Constantine region.
Materials and Methods: A retrospective, observational, cross-sectional study was conducted on 551 vaccinated children in the Constantine region. Quantitative measurement of anti-HBs antibodies was performed using an ELISA technique (seroprotection threshold set at >=10 IU/L) at the Constantine University Hospital. HBsAg, anti-HBc, HBeAg, and anti-HBe markers were also screened to assess viral circulation. Data were analyzed using SPSS v.21 software (statistical significance threshold set at p < 0.05).
Results: The overall vaccine seroprotection rate was 89.84% (n = 495), of whom 57.35% exhibited strong immunity (>100 IU/L). Older age at testing (p < 0.001), birth weight abnormalities (p < 0.001), non-compliance with the vaccination schedule (p < 0.001), and positive maternal HBsAg status (p < 0.001) significantly influenced post-vaccination immunization. Seroprevalences of 1.27% for HBsAg (7/551) and 2.18% for anti-HBc (12/551) were observed, indicating breakthrough infections or vertical transmission. Among children born to HBsAg-positive mothers, specific comorbidities such as type 1 diabetes (p < 0.001) and biological anemia (p < 0.011) were strongly associated with serological non-response.
Conclusion: The Algerian EPI ensures robust overall immunological coverage. Nevertheless, the insufficient seroprotection rate observed in children exposed to vertical transmission necessitates the implementation of systematic prenatal screening, rigorous post-vaccination serological follow-up, and standardized immunoprophylaxis (combining vaccine and specific immunoglobulins) within the first 24 hours of life. Finally, personalized management of children suffering from metabolic or hematological comorbidities is indispensable to optimize the overall efficiency of this national program.