Study of HBV Therapeutic Vaccines GS-2829 and GS-6779 in Healthy Participants and Participants With Chronic Hepatitis B

Key Inclusion Criteria: Phase 1a and 1b: * Body mass index (BMI) of ≤ 32.0 kg/m\^2. * Non-diabetic without impaired glucose tolerance. * No evidence of cardiac disease based on 12 lead electrocardiogram (ECG). Phase 1a (Healthy Individuals) only: * Aged 18 through 60 years. * No prior history of Hepatitis B infection with a negative hepatitis B surface antigen (HBsAg) and Hepatitis B (HBV) core antibody. Phase 1b (Virally Suppressed chronic hepatitis B (CHB) Individuals)): * Aged 18 through 65 years. * Documented CHB and HBsAg ≤ 5000 IU/mL at screening. * No evidence of advanced fibrosis by Fibroscan (defined as Fibroscan \< 9 kilo pascal (kPa) within 6 months of screening). * Diagnosed with CHB on suppressive oral antiviral for ≥ 6 months. * Must have received an approved HBV-active oral antiviral agent for ≥ 6 months prior to screening with HBV DNA below lower limit of quantification (LLOQ) for ≥ 3 months prior to screening and with no plan to stop HBV-active antivirals during the study. Key Exclusion Criteria: Phase 1a and 1b: * Use of any systemic antibiotics within 30 days of screening. * Receipt of any HBV vaccine within 12 months of screening visit or planning HBV vaccination during the study period. * Receipt of any investigational product within 3 months or vaccine within 3 months of screening (with the exception of influenza and severe acute respiratory syndrome (SARs) coronavirus (COV) - 2 (SARS-CoV-2) vaccines, which if needed, should be administered at least 14 days before or after an investigational product administration). * Receipt of immunoglobulin or other blood products within 3 months of screening. * Positive serum pregnancy test at screening or positive urine pregnancy on Day 1. * Have been treated with systemic steroids, immunosuppressant therapies, or chemotherapeutic agents within 3 months prior to screening or is expected to receive these agents during the study (eg, corticosteroids, immunoglobulins, other immune or cytokine-based therapies). * Participation in any other clinical study (including observational studies) without prior approval from the sponsor is prohibited while participating in the study. Note - Other protocol defined Inclusion/Exclusion criteria may apply.