Immunogenicity, Safety, and Clinical Outcomes Following Homologous and Heterologous SARS-CoV-2 Vaccination Regimens in Patients with Axial Spondyloarthritis and Psoriatic Arthritis: A Prospective Observational Study from the SAFER Cohort
Vanessa de Oliveira Magalhães, Priscila Dias Cardoso Ribeiro, Flávia Maria Matos Melo Campos Peixoto, Erika Biegelmeyer, Mariana Freitas de Aguiar, Cristiane Kayser, Alexandre Wagner Silva de Souza, Charlles Heldan de Moura Castro, Ketty Lysie Libardi Lira Machado, José Geraldo Mill, Nésio Fernandes de Medeiros Junior, Danielle Cristina Filgueira Alves Batista, Rebeca Silva Moreira da Fraga, Thaisa de Moraes Ribeiro Espirito Santo, Samira Tatiyama Miyamoto, Gabriel Smith Sobral Vieira, Pietra Zava Lorencini, Bárbara Oliveira Souza, Heitor Filipe Surlo, Anna Carolina Simões Moulin, Paula dos Santos Athayde, Mariana de Oliveira Macabú, Sandra Lúcia Euzébio Ribeiro, Raquel Lima de Lima, Natália Seixas de Melo, Russian Teixeira Rebello, Marcos Mavignier Sousa Dias, Jonathan Willian da Silva Rodrigues, Camila Maria Paiva França Telles, Natália Sarzi Sartori, Regiane Lima, Rodrigo Poubel Vieira de Rezende, Katia Lino Baptista, Rodrigo Cutrim Gaudio, Ana Karla Guedes de Melo, Valéria Bezerra da Silva, Vitor Alves Cruz, Jozelia Rêgo, Rejane Maria Rodrigues de Abreu Vieira, Adah Sophia Rodrigues Vieira, Adriana Maria Kakehasi, Anna Carolina Faria Moreira Gomes Tavares, Artur José Azevedo Pereira, Renata Henriques de Azevedo, Valderilio Feijó Azevedo, Olindo Assis Martins-Filho, Vanessa Peruhype-Magalhães, Emilia Inoue Sato, Ricardo Machado Xavier, Andréa Teixeira-Carvalho, Viviane Angelina de Souza, Gilda Aparecida Ferreira, Edgard Torres dos Reis-Neto, Odirlei André Monticielo, Valéria Valim, Gecilmara Salviato Pileggi, Marcelo de Medeiros PinheiroBackground/Objectives: Patients with spondyloarthritis (SpA) frequently receive immunomodulatory therapies that may influence vaccine-induced immune responses. However, evidence comparing the immunogenicity, safety, and clinical outcomes following homologous and heterologous SARS-CoV-2 vaccination regimens in axial spondyloarthritis (axSpA) and psoriatic arthritis (PsA) remains limited. Methods: This observational study was conducted within the Brazilian multicenter SAFER cohort and included adults with axSpA or PsA who received three doses of SARS-CoV-2 vaccines through the Brazilian National Immunization Program. The primary outcome was humoral immunogenicity, assessed by anti-receptor-binding domain (anti-RBD) IgG geometric mean titers (GMTs). Clinical outcomes, disease activity, and safety were evaluated throughout follow-up. Results: Ninety patients (axSpA = 69; PsA = 21) were included. Antibody titers increased progressively after vaccination, with GMTs rising from 6.70 BAU/mL at baseline to 907.72 BAU/mL after the additional dose. Humoral responses were comparable between axSpA and PsA throughout follow-up. Participants with previous SARS-CoV-2 exposure consistently exhibited higher antibody responses than infection-naïve individuals. Although ChAdOx1-S elicited stronger early humoral responses than CoronaVac, heterologous regimens incorporating a BNT162b2 additional dose produced the highest post-additional-dose antibody concentrations. Serological response rates reached 100% after the additional dose, irrespective of disease subtype or vaccination regimen. Biologic disease-modifying antirheumatic drugs (bDMARDs), including TNF inhibitors, were not significantly associated with reduced antibody responses. Only four COVID-19 cases occurred during follow-up, with no hospitalizations or deaths. Disease activity remained stable, and adverse events were predominantly mild and self-limited. Conclusions: SARS-CoV-2 vaccination was safe and highly immunogenic in patients with axSpA and PsA, without compromising disease activity control. Heterologous vaccination regimens incorporating a BNT162b2 additional dose elicited the strongest humoral immune responses. These findings provide prospective real-world evidence supporting optimized additional-dose strategies and may inform future vaccination approaches for patients with SpA.