Assessing the Impact of Hepatitis B Immune Globulin (HBIG) on Responses to Hepatitis B Vaccine During Co-Administration.

Introduction: A hepatitis B vaccination (HepB) series with an initial dose of hepatitis B immune globulin (HBIG) is the recommended prophylaxis for infants born to mothers with chronic hepatitis B virus (HBV) infection and for HBV-exposed persons without known protection. The HepB and HBIG are administered at different sites (limbs). Instances of HepB and HBIG administered at the same site are documented but the impact on immune responses to HepB remains unanswered. Methods: Newborn and adult BALB/c mice received one dose of HepB at time zero alone or with HBIG in the same or different sites, followed by 2 additional doses of HepB at 3 and 10 weeks (newborn mice) or 4 and 16 weeks (adult mice). To study memory responses mice were given a 4th, booster, dose of HepB at 26 weeks and B cells analyzed. Results: Administration of HepB with HBIG resulted in reduced responses to HepB following the first 2 doses, regardless of site, compared to mice that received HepB only. Lower levels of antibody to HBV surface antigen (anti-HBs) were observed at the end of the 3-dose series (p < 0.0001) in all groups of newborn mice that received HepB and HBIG. In adult mice, this difference was only seen when HepB and HBIG were delivered at the same site. However, following a HepB booster at 26 weeks, HBsAg-specific B-cell expansion and memory phenotype were not impacted by initial HBIG administration Conclusion: Administration of HBIG with HepB can delay and reduce responses to HepB in mice. Our findings suggest that the initial circulating levels of HBIG could prevent infection despite an impaired response to vaccine and support the current recommendation of assessing seroprotection after series completion for infants born to HBV carrier mothers, including in cases where vaccine and HBIG are administered incorrectly at the same site. Published by Elsevier Ltd. This is an open access article under the CC BY-NC license (http://creativecommons.org/licenses/by-nc/4.0/).