Characteristics of Coronavirus Disease in Allogeneic Hematopoietic Stem Cell Transplantation During the Omicron Wave: A Single-Center Study.

Objectives: This study aimed to characterize the clinical characteristics, outcomes, and risk factors for coronavirus disease 2019 (COVID-19) in 492 patients who underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT) during the Omicron wave. Methods: Data were retrospectively collected from patient charts and the electronic medical record systems at the First Affiliated Hospital of Zhejiang University School of Medicine between December 2022 and January 2023. Results: The median follow-up period of the entire cohort was 62 days. Myeloid malignancies (58.5%) and acute lymphocytic leukemia (30.5%) constituted the most common underlying disease. Among the 492 patients, 415, 67, and 10 exhibited mild, moderate, and severe COVID-19, respectively. The incidence of moderate-to-severe COVID-19 was 15.7%. The 60-day overall survival and complete resolution rates were 98.1% and 80.6%, respectively. The risk factors for moderate-to-severe COVID-19 included corticosteroid use within 3 months before diagnosis, <6 months interval between allo-HSCT and COVID-19 diagnosis, and antithymocyte globulin use for graft-versus-host disease prophylaxis. Conclusions: During the Omicron wave, patients with allo-HSCT demonstrated a low COVID-19-related mortality rate and high moderate-to-severe and prolonged disease incidence. Prevention in the early posttransplantation period is critical for allo-HSCT recipients receiving corticosteroids.