Respiratory syncytial virus in hematopoietic cell transplant recipients and patients with hematologic malignancies

Khawaja, Fareed; Chemaly, Roy F.

High mortality rates have been reported in HM patients and HCT recipients with RSV infection. RSV-attributable mortality rates in HCT recipients vary between 0% in outbreak situations, 48, 62, 67 in which some patients received reduced-intensity conditioning regimens, 62 and 43% in other circumstances. 5, 20, 22, 24, 25, [42] [43] [44] [45] [46] [47] [48] [49] [50] [51] When HCT recipients develop RSV LRTI, the mortality rate can range from 21% to 83% 4, 31, 42, 43, 45, 46, 48, 68 Of note, when HCT recipients with RSV infections were classified into those with possible RSV LRTI (only radiological evidence of chest abnormalities and negative or no bronchoscopy data) or proven RSV LRTI (RSV detected in the lower respiratory tract), 31 the mortality rate increased from 0% to 26%, respectively. 31 Multiple other risk factors for mortality from RSV have been identified, most of which are host-related, including neutropenia and lymphopenia, time from transplant to infection, cell source, older age, steroid exposure, graft-versus-host disease, hypoxia, and the use of myeloablative chemotherapy. 25, 42, 43, 46, 47 The RSV-ISI has been validated to predict mortality risk in HCT recipients 12, 53, 56 (Table 2) . Based on the derivative cohort of allogeneic HCT recipients with RSV infections, the predicted mortality for patients with high RSV-ISI was 29% 53 and 50% in one of the validation cohorts. 44 Interestingly, some studies showed that ribavirin may have a protective effect in HCT recipients and HM patients. 37, 42, 44, 53, 58 This is discussed further in the treatment section.