Prognostic factors for the development of lower respiratory tract infection after influenza virus infection in allogeneic hematopoietic stem cell transplantation recipients: A Kanto Study Group for Cell Therapy multicenter analysis

Objectives: Influenza virus infection (IVI) occasionally causes lower respiratory tract infection (LRTI) in allogeneic hematopoietic stem cell transplantation (allo-HSCT) recipients. Although the progression to LRTI entails a high mortality, the role of early antiviral therapy for its prevention has not been fully elucidated. Methods: This was a multicenter retrospective study using an additional questionnaire. Allo-HSCT recipi-ents who developed IVI between 2012 and 2020 were included.Results: A total of 278 cases of IVI after allo-HSCT were identified from 15 institutions. The median patient age was 49 years, and the median time from allo-HSCT to IVI was 918 days. Neuraminidase inhibitors were administered within 48 hours of symptom onset (early neuraminidase inhibitor [NAI]) in 199 (76.9%) patients. Subsequently, 36 (12.3%) patients developed LRTI. On the multivariate analysis, age >= 50 years (hazard ratio [HR], 2.16; 95% confidence interval [CI], 1.02-4.58) and moderate to severe chronic graft-versus-host disease (HR, 2.28; 95% CI, 1.14-4.58) were significantly associated with progres-sion to LRTI, whereas early NAI suppressed the progression (HR, 0.17; 95% CI, 0.06-0.46). The IVI-related mortality rate was 2.2%.Conclusion: To reduce the risk of LRTI development after IVI, early NAI therapy should be considered in allo-HSCT recipients, especially with older patients and those with chronic graft-versus-host disease.(c) 2023 The Authors. Published by Elsevier Ltd on behalf of International Society for Infectious Diseases. This is an open access article under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ )