Respiratory syncytial virus prefusion F3 vaccine in lung transplant recipients elicits CD4+ T cell response in all vaccinees

Respiratory syncytial virus (RSV) causes seasonal acute respiratory illness significantly impacting vulnerable groups, including lung transplant recipients, who are at increased risk of hospitalization, acute rejection, and allograft dysfunction. The immunogenicity of the novel RSV prefusion F3 (RSVPreF3-AS01, Arexvy, GlaxoSmithKline) vaccine in immunocompromised patients remains largely unknown. In this study, we assessed both antibody-using and cellular immune responses 2 months after a single dose of the RSVPreF3-AS01 vaccine in 30 lung transplant recipients aged 60 years or older, who were at least 6 months posttransplant. The antibody response was assessed using enzyme-linked immunosorbent assay for detection of serum anti-RSV-F IgG specific antibodies, and the CD4+ T cell response was measured by flow cytometry intracellular cytokine secretion assay. Our findings show that all vaccinees exhibited a CD4+ T cell response 2 months postvaccination, whereas only 40% demonstrated an antibody response. These results suggest that some patients may derive clinical benefit from the vaccine through cellular immunity, even without an antibody response. Furthermore, the vaccine was well tolerated in this vulnerable population, with no major safety concerns observed.