Please provide information about the adult HepB vaccine PreHevbrio (VBI Vaccines), which is no longer available in the United States.

PreHevbrio (VBI Vaccines) was approved by the FDA in November 2021 for people age 18 years and older. It is a triple-antigen (containing S, Pre-S1, and Pre-S2 HBV surface proteins) recombinant vaccine produced in mammalian cells (Chinese hamster ovary cells), and containing an alum adjuvant. It is given intramuscularly in a 3-dose series of 1.0 mL (10 mcg) doses administered on a 0-, 1-, and 6-month schedule.

PreHevbrio was approved based on clinical trials conducted in adults age 18 years and older that compared seroprotection rates (SPR, defined as anti-HBs of 10 mIU or higher, and indicative of protection against HBV infection) following 3 doses of PreHevbrio to rates following 3 doses of Engerix-B (GSK). The SPR for PreHevbrio among adults age 18 years or older ranged from 83.6% to 99.2% (overall, 91.2% for all adults) compared to Engerix-B, which ranged from 64.7% to 91.1% (overall, 76.5% for all adults).

All doses of PreHevbrio were withdrawn from the U.S. market in late 2024 for business reasons following the bankruptcy of the manufacturer, VBI Vaccines. There were no safety or quality issues with the vaccine product. All properly administered doses of PreHevbrio are valid. A 3-dose series of HepB vaccine initiated with PreHevbrio may be completed with any other age-appropriate HepB product. Follow the dosing intervals for a 3-dose HepB vaccine series if completing vaccination with Engerix-B (GSK) or Recombivax HB (Merck). If two doses of Heplisav-B (Dynavax) are used after a single dose of PreHevbrio, the minimum interval between the two Heplisav-B doses is 4 weeks, which constitutes a complete 2-dose Heplisav-B series.