SOLSTICE: Combination Therapy for the Treatment of Chronic Hepatitis D Infection.

This is a phase 2 trial in which participants with chronic hepatitis D virus (HDV) infection will receive VIR-2218 and/or VIR-3434 and be assessed for safety, tolerability, and efficacy

Participants may be enrolled into Cohort 1 (1a and 1b) or Cohort 2 (2a, 2b1 or 2b2, 2c), 3, 4, and 5. All participants still receiving VIR-2218 or VIR-3434 monotherapy at the time of implementation of Protocol Amendment 4 will switch to combination therapy at Week 132 (Cohort 2a, 2b1/2b2) or Week 112 (Cohort 3).

Inclusion Criteria: * Male or female ages 18 to \< 70 years at screening * Chronic HDV infection for \>/= 6 months * On NRTI therapy for at least 12 weeks prior to day 1 * ALT\>ULN and \< 5x ULN * Non-cirrhotic and CPT-A cirrhotic Exclusion Criteria: * Any clinically significant chronic or acute medical or psychiatric condition that makes the participant unsuitable for participation. * History of significant liver disease from non-HBV or non-HDV etiology * History of allergic reactions, hypersensitivity, or intolerance to study drug, its metabolites, or excipients. * History of anaphylaxis * History of immune complex disease * History of autoimmune disorder * History or evidence of alcohol or drug abuse * Prior or concomitant therapy with an immunomodulatory agent, IFN-alpha, cytotoxic or chemotherapeutic agent, or chronic corticosteroids. * Anti-HBs \>10 mIU/mL at screening