Hospital-mandated restrictions during the COVID-19 pandemic alter hospital-acquired viral respiratory infections during hematopoietic stem cell transplantation: a single center pediatric experience.

Objective: Evaluating the COVID-19 pandemic restrictions and their effect on rates of new respiratory viral infections in patients undergoing hematopoietic stem cell transplantation (HSCT), and if there were changes to the morbidity and mortality rates compared to historical controls. Design: Retrospective chart review. Setting: University-based tertiary care center. Patients: All patients who underwent HSCT, including chimeric antigen receptor T-cell therapy, between 7/1/2013 and 12/19/2021 were included in the study. No eligible patients were excluded. Results: We found a significant difference in new respiratory infections as measured by a respiratory viral pathogen (RVP) polymerase chain reaction-based assay during transplant admissions between the pre- and early COVID-19 eras, with complete absence of new respiratory viral infections in the early COVID-19 era. The late-COVID-19 era, coincident with availability of severe acute respiratory syndrome coronavirus 2 vaccines and relaxation of some hospital-based restrictions, had a similar incidence of new RVP positivity compared to the pre-COVID-19 era. For allogeneic HSCT outcomes alone, rates of pediatric intensive care unit admission (66.7% vs 32.2%, p = .01), intubation (57.1% and 18.6%, p < .01), and oxygen requirement (66.7% vs 40.7%, p = .04) were found to be statistically different with new RVP positivity. Other outcomes examined, including death at 100/180/365 days post-transplant, length of stay, and acute graft-versus-host disease incidence, were similar, regardless of new RVP positivity. Conclusions: In order to reduce morbidity, these findings argue for a continuation of the strict protective isolation practices initially employed during the pandemic for HSCT patients, particularly during viral emergence following the COVID-19 lockdown.