Cellular and humoral immunogenicity of respiratory syncytial virus vaccination in solid organ transplant recipients

Respiratory syncytial virus (RSV) prefusion F-based vaccines have recently been approved for immunosuppressed individuals, but data in solid organ transplant (SOT) recipients remain limited. This observational study assessed natural RSV immunity among 52 controls and 197 patients with immunodeficiencies, of which 46 kidney transplant recipients, 30 lung transplant (LuTx) recipients, and 19 patients with chronic kidney disease subsequently received a single dose of a protein-based RSV vaccine to quantify and characterize RSV-specific antibodies and T cells pre- and postvaccination using enzyme-linked immunosorbent assay and flow cytometry. Reactogenicity was self-reported. Over 90% had natural pan-RSV-specific immunoglobulin G, and 30% to 58% had RSV-specific CD4 T cells. Vaccination was well tolerated and led to a significant increase in antibodies and polyfunctional CD4 T cells (P < .0001), with similar T cell levels to both RSV-subtypes A and B. CD4 T cell responses were comparable between kidney transplant and patients with chronic kidney disease, but significantly lower in LuTx recipients (P = .023) and in SOT recipients within the first year posttransplant (P = .005). The vaccine did not induce any CD8 T cells. In conclusion, a single RSV vaccine dose induced strong immunoglobulin G and CD4 T cell responses with RSV-A/B cross-reactivity. However, LuTx and early posttransplant SOT recipients showed reduced T cell responses. Alternative strategies may be required to improve immunogenicity in heavily immunosuppressed SOT recipients.