Recombinant Herpes Zoster Vaccine in Patients With Autoimmune Rheumatic Diseases Under Immunomodulators

Inclusion Criteria: * Adults aged 18 years or older. * Diagnosis of an autoimmune rheumatic disease (such as rheumatoid arthritis, systemic lupus erythematosus, axial spondyloarthritis, psoriatic arthritis, systemic sclerosis, Sjögren syndrome, idiopathic inflammatory myopathies, or primary systemic vasculitis) according to validated classification criteria. * Clinical stability at the time of enrollment, defined as no change in disease-modifying therapy or corticosteroid dose in the preceding four weeks and no evidence of infection or disease flare. * Current use of hydroxychloroquine or sulfasalazine in monotherapy for at least three months prior to inclusion. * Can be under prednisone use of 5mg/week. * Ability and willingness to comply with study procedures and follow-up visits. * Provision of written informed consent. Exclusion Criteria: * Previous vaccination with recombinant zoster vaccine (RZV). * History of herpes zoster or varicella infection within 12 months before enrollment. * Concomitant use of systemic immunosuppressive therapy including but not limited to methotrexate, mycophenolate mofetil, azathioprine, cyclophosphamide, biologics, or JAK inhibitors. * Use of glucocorticoids \>5mg/week. * Acute febrile illness or active infection at the time of vaccination. * Pregnancy or breastfeeding. * Known hypersensitivity to any component of the recombinant zoster vaccine. * History of Guillain-Barré syndrome. * Any condition that, in the investigators' judgment, could interfere with study participation or interpretation of results.