A Study to Evaluate the Efficacy and Safety of VIB4920 in Participants With Sjögren's Syndrome

Inclusion Criteria: * Diagnosed with SS by meeting the 2016 American College of Rheumatology (ACR)/EULAR Classification Criteria. * Residual salivary gland function as defined by whole stimulated salivary flow \> 0.1 mL/min (only for Population 2). * Have an ESSDAI score of \>= 5 at screening; (not including the peripheral nervous system, central nervous system, and pulmonary domains) (only for Population 1). * Have an ESSPRI score of \>= 5 at screening (only for Population 2). * Have an ESSDAI score of \< 5 at screening (only for Population 2). * Positive for either anti-Ro autoantibodies or rheumatoid factor, or both at screening. * Male and female participants who agree to follow protocol defined contraceptive methods. * No active or untreated latent tuberculosis (TB). Exclusion Criteria: * Medical history of confirmed deep venous thrombosis or arterial thromboembolism within 2 years of signing the informed consent form (ICF). * Risk factors for venous thromboembolism or arterial thrombosis, prothrombotic status. * Concomitant polymyositis or dermatomyositis or systemic sclerosis. * Active malignancy or history of malignancy, except in situ carcinoma of the cervix and cutaneous basal cell carcinoma. * Hepatitis B, hepatitis C, or human immunodeficiency virus infection. * More than one episode of herpes zoster and/or an opportunistic infection in the last 12 months. * Active viral, bacterial, or other infections or history of more than 2 infections requiring intravenous …