Safety and Immunogenicity of the Live Attenuated Tetravalent Butantan-Dengue Vaccine in Autoimmune Rheumatic Diseases

The goal of this clinical trial is to evaluate whether the live attenuated tetravalent Butantan-Dengue vaccine (Butantan-DV) is safe and capable of inducing an immune response in patients aged 12 to 59 years with autoimmune rheumatic diseases (ARDs) who are clinically stable and under low-grade or no immunosuppression, as well as in healthy volunteers matched by sex and age. The main questions it aims to answer are: Does the vaccine induce adequate seroconversion in patients with ARDs compared to healthy controls? What is the frequency and intensity of common adverse events after vaccination in ARDs patients? Does physical activity levels and nutritional status influence vaccine-induced immune response in patients with ARDs? Researchers will compare patients with ARDs to healthy controls to evaluate if the vaccine elicits similar immune responses and safety profiles. All participants will: * receive a single 0.5 mL dose of the Butantan-DV vaccine via subcutaneous injection; * undergo blood sample collection before and after vaccination (baseline, Day 42, and Day 400) to assess antibody and cellular responses; * attend follow-up visits on Days 7, 14, and 42 for safety monitoring and laboratory tests; * report any symptoms or adverse events using a standardized diary for 42 days; * be followed for up to one year for long-term safety and immunogenicity assessments. * wear a device for 14 consecutive days to assess current and habitual physical activity levels. * answer three non-consecutive 24-hour dietary recalls, including at least one weekend day to assess nutritional status. * collect blood samples one-year after vaccination to access immunogenicity and cellular response. Researcher will also perform subgroups analysis in: A viremia subgroup (50 patients and 50 healthy controls) will provide additional samples on Days 1, 7, 14, 28, 42, and-if viremia is detected-Day 68, to evaluate post-vaccination viremia and its duration. An immunogenicity subgroup (\~20% of participants, n=96) will undergo cellular immune response testing via flow cytometry to evaluate T-cell responses.

NCT Number	NCT07087912
Lead Sponsor	University of Sao Paulo General Hospital Collaborators: Butantan Institute
Conditions	Rheumatoid Arthritis (RA), Juvenile Idiopathic Arthritis (JIA), Systemic Lupus Erythematosus (SLE), Juvenile Systemic Lupus Erythematosus, Systemic Sclerosis (SSc), Idiopathic Inflammatory Myopathies (IIMs), Axial Spondyloarthritis, Psoriatic Arthritis (PsA) +4 more
Enrollment	477 participants
Start Date	2026-03-16
Primary Completion	2027-12-30 (estimated)
Study Completion	2028-12-30 (estimated)
Updated on ClinicalTrials.gov	2026-07-20