Bone Marrow Transplant - Autologous or Allogeneic

This study evaluates whether the RSV vaccine Abrysvo can produce an antibody response in patients with blood cancers who have previously received a hematopoietic stem cell transplant (HSCT) or CAR-T cell therapy. The vaccine targets the prefusion F (preF) protein of RSV, which is an important component of protective immunity against the virus. The main goal of the study is to measure the change in antibody levels against the preF protein four weeks after vaccination compared with levels before vaccination. The study will also assess whether participants develop a meaningful immune response, defined as at least a four-fold increase in RSV neutralizing antibody levels four weeks after vaccination.