Immunologic pattern of hepatitis B infection among exposed and non-exposed babies in A PMTCT program in low resource setting: Does every exposed newborn require 200IU of hepatitis B immunoglobulin?

Background: Hepatitis B (HBV) is a vaccine-preventable infection. Vaccination programs instituted for virtual elimination of vertical and horizontal transmission are rarely evaluated. The prohibitive cost of HBV immunoprophylaxis (HBIG) engenders restrictive access in low-resource settings. Objective: Comparison of the immunologic pattern of HBV seromarkers and mother-to-child transmission (MTCT) rates among exposed and non-exposed babies who received either standard 200 iu or 100 iu HBIG in resource low settings. Method: This prospective pilot observational study involved a cohort of HBV-infected pregnant women and exposed babies and HBV-uninfected women-baby pairs as control at the Department of Obstetrics and Gynecology, UBTH, Nigeria. HBV seromarkers were detected using rapid, direct, third generation immunochromatographic test for qualitative monoclonal and polyclonal anti-HBsAg antibodies. Reactive samples were reanalyzed using LumiQuick HBV-5 panel test for visual detection of HBs-antigen, anti-HBs-antibodies, HBe-antigen, anti-HBe antibodies, anti-HBc(IgG/IgM) antibodies. Reactive samples were confirmed with ELISA. Exposed babies were "self-selected" into receiving either 200 IU or 100 IU HBIG within 12 hours of birth plus 3-dose course of HBV vaccine. Outcome measures were incidence of MTCT of HBV, pattern of immunologic response for HBV seromarkers and proportion of vaccine non-responders. Results and conclusion: The MTCT rate was 0.0% for all groups with no homogenous pattern of maternal to fetal transfer of HBV seromarkers. The overall rate of non-response to vaccination was high (8.0%) with exposed infants being poorer responders (17.1%) to vaccination p<0.01. We advocate introduction of HBIG as integral part of care into the NPI program and multicenter studies to evaluate our findings before policy change. © 2013 Onakewhor JUE, et al.