Anti-HBs antibody levels among HB-vaccinated children attending public health facilities in Bahir Dar (northwest Ethiopia) and investigation of associated factors

Abstract

Objective This study aimed to assess HB vaccine seroprotection levels and associated factors among vaccinated children in Bahir Dar, northwest Ethiopia. Study design Cross sectional. Methods A health facility-based cross-sectional study was conducted involving a total of 325 vaccinated children in Bahir Dar from December 2023 to June 2024. Data on sociodemographic characteristics and possible predictors were collected using a structured questionnaire, and serum samples were screened for anti-HBs using sandwich MAGLUMI chemiluminescence immunoassay (CLIA). Data were entered and analyzed using SPSS version 23 software. Logistic regression was used to check the association between variables using OR at 95% CI. P -value ≤0.05 was considered statistically significant. Results Most of the children (227; 69.8%) were in the 1–4-year age group. The HB vaccine seroprotection rate was 55.1% (95% CI; 49.5–60.3). Among seroprotected children, 34.6% were good responders (anti-HBs titer ≥100 mIU/mL), and 65.4% were hypo-responders (anti-HBs titer 10–99 mIU/mL). The proportion of children exhibiting seroprotective anti-HBs levels was 135 (59.5%) among those aged 1–4 years, 35 (49.3%) in the 5–9 years group, and 9 (33.3%) among those aged 10–14 years. The age of children (AOR: 3.7; 95% CI: 1.2–11.6; p = 0.023) and the type of health facility where the HB vaccine was administered (AOR: 2.1; 95% CI: 1.1–4.2; p = 0.034) were found to be significantly associated with HB vaccine effectiveness. Conclusion Generally, suboptimal seroprotection levels of HB vaccine was reported in this study. The age of children and the type of health facility where the HB vaccine was administered were significantly associated with HB vaccine effectiveness. These findings call for enhanced public health strategies to effectively reduce HBV infection.