VBI Vaccines Inc. announced that results from a Phase 4 study of VBI's prophylactic 3-antigen Hepatitis B virus (HBV) vaccine in younger adults were published in Vaccine, a journal publication from Elsevier. The study was designed to evaluate the immunogenicity of VBI's 3-antigen HBV vaccine in support of the qualification of that batch as a new reference standard for vaccine release to the Israeli market, where VBI's vaccine is available as Sci-B-Vac. Prior to market release in Israel, batches of VBI's vaccine are tested against a reference vaccine batch that has been assessed in a clinical trial. According to the European Pharmacopeia, the reference batch should elicit, after the full course of vaccination, a seroprotection rate (SPR) of at least 95% in young and healthy adult participants. In this open-label, single-arm Phase 4 study in 91 healthy adults age 20-40 years, this objective was achieved two months after the second dose ­ the SPR at month 3 was 98.8% [95% CI: 93.7%, 99.7%]. SPR is defined as the % of participants who achieve antibody titers (anti-HBs titers) above the protective threshold of 10 mIU/mL. Additional results from this Phase 4 study include: By month 7, after receiving three doses, all enrolled participants (100%) were seroprotected; The majority of participants were high responders, defined as achievement of anti-HBs titers 100 mIU/mL ­ high-responder SPR was 81.4% and 97.6% at month 3 (after 2 doses) and month 7 (after 3 doses), respectively; The geometric mean concentration (GMC) of anti-HBs titers were also substantially above the protective threshold at 413.6 mIU/mL and 6799.9 mIU/mL at month 3 and month 7, respectively; Anti-HBs titers were maintained above 2000 mIU/mL at month 12, suggesting a potent and sustained response; and Consistent with other clinical data, VBI's 3-antigen HBV vaccine was well-tolerated with no safety signals observed. Participants in this study were immunized with 10 µg of VBI's HBV vaccine at months 0, 1, and 6.