CMV-MVA Triplex Vaccination of Stem Cell Donors in Preventing CMV Viremia in Participants With Allogeneic Transplant

PRIMARY OBJECTIVES: I. Establish the feasibility and safety of priming CMV immunity in donors by Triplex vaccination prior to peripheral blood stem cell (PBSC) harvest. SECONDARY OBJECTIVES: I. Examine if Triplex vaccination of hematopoietic stem cell transplant (HCT) donors has an impact on CMV events. OUTLINE: Donors receive multi-peptide CMV-modified vaccinia Ankara vaccine injection between days -60 and -10 prior to granulocyte colony stimulating factor mobilization. Participants undergo hematopoietic cell transplantation on day 0. After completion of study treatment, participants are followed up for 1 year.