Comparison of safety and immunogenicity of two doses of investigational hepatitis B virus surface antigen co-administered with an immunostimulatory phosphorothioate oligodeoxyribonucleotide and three doses of a licensed hepatitis B vaccine in healthy adul

► Two doses of an HBV-ISS demonstrated superior immunogenicity to three doses of HBV-Eng measured at week 28. ► HBV-ISS had a safety profile that was similar to the currently licensed HBV-Eng although injection-site reactions were more common. ► HBV-ISS achieved higher levels of protection after the first and second doses.