Abstract Reports on vaccine immunogenicity in patients with systemic autoimmune rheumatic diseases (SARDs) have been inconclusive. Here, we report the immunogenicity of heterologous prime-boost with an inactivated vaccine followed by an adenoviral vector vaccine in patients with SARDs using anti-RBD antibodies, neutralizing capacity against Omicron BA.2 [plaque-reduction neutralization test (PRNT)], T cell phenotypes, and effector cytokine production at 4 weeks after vaccination. SARD patients had lower median (IQR) anti-RBD-IgG levels and neutralizing function against the Omicron BA.2 variant than the healthy group (p = 0.003, p = 0.004, respectively). T cell analysis revealed higher levels of IFN-γ- and TNF-α-secreting CD4 + T cells (p < 0.001, p = 0.0322, respectively) in SARD patients than in the healthy group. Effector cytokine production by CD8 + T cells was consistent with Th responses. These results suggest that this vaccine regimen revealed mildly impaired humoral response while preserving cellular immunogenicity and may be an alternative for individuals for whom mRNA vaccines are contraindicated.
