RecruitingPhase 1Biological interventionT Cell Therapy Opposing Novel COVID-19 Infection in Immunocompromised PatientsThis is an open label, phase I dose-escalation study to evaluate the safety of coronavirus-specific T cell (CST) therapy for prevention of SARS-CoV-2 infection in immunocompromised patients following hematopoietic stem cell transplantation (HSCT). Participants will receive donor-derived CSTs for prevention of SARS-CoV-2 infection after HSCT (≥28 days and \<4 months after HSCT). In this dose escalation trial, three doses (1x107/m2, 2x107/m2, and 4x107/m2) will be tested for safety, with study arms for adult (≥18 years of age and \<80 years) HSCT recipients (Arm A) and two arms for pediatric (≥12 years of age and \<18 years; ≥2 years and \<12 years) HSCT recipients (Arm B and Arm C, respectively), and defined dose escalations in each study arm. The study agent will be assessed for safety (stopping rules defined) and antiviral activity.