1051 - Rapid onset of seroprotection rates in young adults immunized with a tri-antigenic hepatitis B virus (HBV) vaccine compared to a mono-antigenic HBV vaccine

Background: Hepatitis B (HBV) remains a significant public health risk with an estimated 240-350 million people chronically-infected with HBV worldwide. In the US, rates of new HBV infections are highest among individuals aged 30-39 years, highlighting the elevated risk in adults.  Moreover, CDC reported that in 2017 only 34.3% of US adults aged 19-49 years were vaccinated against HBV. Younger adults who are at-risk of HBV infection, through exposure in the workplace or home (e.g. healthcare workers, public service sector workers, those living with HBsAb-positive individuals), through travel to countries with high HBV prevalence, or through exposure as a result of high-risk behavior (e.g. injection drug use, risk through sexual transmission), need a highly effective and safe HBV vaccine with a rapid onset of seroprotection.Seroprotection Rates from Phase 3 Studies


Methods: Four phase 3 studies assessing kinetics of seroprotection rates (SPR; anti-HBs ≥ 10 mIU/mL) in adults aged 18-45 years, vaccinated at months 0, 1 and 6 with 10 µg of tri-antigenic  HBV vaccine (TAV) vs. 20 µg of a mono-antigenic HBV vaccine (MAV) were completed between 2008 & 2020: (1) PROTECT study in US, Europe, and Canada, n = 299; (2) CONSTANT study in US, Europe and Canada, n = 2,838; (3) SG-005-05 study in Vietnam, n = 349; (4) 38-13-040 study in Russia, n = 99. One phase 4, single-arm study was conducted with 10 µg of TAV in adults aged 20-40 years: SciB018 study in Israel, n = 83.

Results: In all five studies, vaccination with TAV achieved SPRs of 87.2-100.0% at month 6 after 2 doses and 99.2-100.0% at month 7 after 3 doses, compared to 39.0-89.4% and 91.1-98.3% achieved with MAV at months 6 and 7, respectively (Fig 1). Moreover, as demonstrated with the data available from two of the controlled studies, TAV induced SPRs of 76.0%-95.9% at month 3 after 2 doses compared to 37.2%-87.2% with MAV.  No major safety signals were observed, and adverse events were well-balanced and consistent with the known vaccine safety profiles.

Conclusion: Tri-antigenic HBV vaccine (TAV) has demonstrated its ability to rapidly, consistently, and safely elicit high SPRs in younger adults across different regions of the world.