Safety and immunogenicity of different two-dose regimens of an investigational hepatitis B vaccine (hepatitis B surface antigen co-administered with an immunostimulatory phosphorothioate oligodeoxyribonucleotide) in healthy young adults

► A 0-4-week schedule of HBV-ISS was as well tolerated as a 0-8-week schedule. ► 2 doses of HBV-ISS at 0-4-week achieved similar seroprotection as a 0-8-week schedule. ► Differences in GMTs had diminished in magnitude by 32 weeks post vaccination.