Inclusion Criteria:  Patients must be capable of understanding and providing a written informed consent, or, if too ill to give consent, have a legal guardian or power of attorney able to provide written informed consent on their behalf Patients must be at least 18 years of age, of any gender, race, or ethnicity Patients must be in morphologic remission from their underlying disease prior to transplant (measurable residual disease permitted) Patients must be undergoing HCT (any donor or stem cell source, including autologous or cord blood transplant) History of prior transplants are permitted History of COVID-19, history of vaccination for SARS-CoV-2, positive polymerase chain reaction (PCR) of a respiratory specimen for SARS-CoV-2, or seropositivity for SARS-CoV-2 are permitted History of SARS-CoV-2 infection or vaccination of the donor are permitted. Post-enrollment vaccination is anticipated and permitted Administration of IVIG before or during the study is permitted  Exclusion Criteria:  Relapse of underlying malignancy Signs or symptoms of uncontrolled, active infection Pregnant or breastfeeding (this population is generally not cleared for transplant) Previous known allergies to any component of the mAb Previous anaphylaxis or severe hypersensitivity reaction, including angioedema, to a mAb Participants of other clinical studies that preclude the use of other investigational compounds Participants who, in the judgment of the investigator, will be unlikely or unable to comply with the requirements of the protocol or unlikely to survive to the end of study