Clinical Effects of COVID-19 on Hematopoietic Stem Cell Transplant Outcomes in Pediatric Patients.

Coronavirus disease 2019 is the third zoonotic acute respiratory disease after SARS virus and Middle East respiratory syndrome. Most cases are mild in healthy children. In contrast, the infection is more severe in patients with underlying health conditions. Because there are few posttransplant reports in hematopoietic stem celltransplant patients, here we described COVID19 infection in 4 confirmed cases among pediatric hematopoietic stem cell transplant recipients: 3 boys and 1 girl with a median age of 6 years. Three patients presented with symptoms of lower respiratory tract disease, whereas 1 patient presented with extrapulmonary symptoms without fever or pulmonary involvement. All of the patients were on immunosuppressivedrugs, ie, 1patientforgraft-versus-hostdisease prophylaxis and 3 patients for graft-versus-host disease treatment.Thosewhowerediagnosedwith active graftversus-hostdisease requiredmechanical ventilationand intensive care. Two patients died from multiple organ dysfunction and resistant coinfection, and 1 patient developed pulmonary hypertension and mild cardiomegaly and remained at the hospital for more than 2 months, whereas the patient with no graft-versus-host disease was discharged and recovered. Our findings showed that COVID-19 infection among hematopoietic stem cell transplant recipients may be more severe and associatedwithlong-termhospitalization and complications. Active graft-versus-hostdisease, coinfections, and long-term use of immunosuppressive agents are risk factors for poor outcomes.