Birgitta Versluijs

97 Good outcome of untreated RSV in pediatric HCT Introduction Children with immunodeficiency are at increased risk for complicated respiratory syncy- tial virus (RSV) disease. Hematopoietic cell transplant (HCT) recipients are considered particularly vulnerable for progression to lower respiratory tract infection (LRTI) and RSV-related mortality. 1 In adult HCT-patients with RSV, antiviral therapy with ribavirin is suggested to lead to better outcome. 2 Several important groups, including the European Conference on Infection in Leukemia (ECIL-4) recommend treatment with ribavirin and intravenous immunoglobulin (IVIG) in HCT-recipients. 3,4 Not much is known about the natural course of RSV in pediatric HCT-patients. Because of a lack of well-designed trials on the efficacy of antiviral therapy, treatment of RSV in this context remains controver- sial. Here, we describe be the incidence and outcome of untreated RSV-infection in a cohort of pediatric HCT-recipients. Methods All consecutive patients, undergoing first HCT between 2004 and 2015 at Wilhelmina Children’s Hospital, UMCUtrecht, The Netherlands, were included. According to local screening policy, 5 all patients were routinely tested for respiratory viruses, including RSV, by polymerase chain reaction (PCR) in nasal pharyngeal aspirate (NPA) and/or bron- choalveolar lavage (BAL) prior to HCT. 5 Tests were repeated in patients that developed (new) respiratory symptoms after HCT. In case of PCR positivity, elective HCT procedu- res were postponed for two weeks, aiming for clearance of the virus. When underlying disease did not allow treatment delay, immune suppression was continued for a longer period after HCT, because earlier studies have shown that respiratory virus infection is a predictor for allo-immune mediated lung disease. Prolonged immunosuppressive therapy was suggested to prevent this life-threatening event. 6 Immunoprophylaxis by palivizumab or antiviral treatment with ribavirin was never used. Patients were classified either (1) asymptomatic, (2) upper respiratory infection (URTI) with signs of rhinitis, otitis media or pharyngitis, or (3) LRTI when tachypnea, dyspnea, wheezing, cough or hypoxia was present . Development of RSV-infection within the first three days of hospitalization was considered community acquired. RSV-patients were scored using the Immunodeficiency Scoring Index for RSV-infection (ISI-RSV) in HCT- recipients. 7 This score combines neutrophil count, lymphocyte count, age, myelo-ablative regimen, GVHD, corticosteroids and recent engraftment or pre-engraftment. It predicts the risk of progression to LRTI and RSV-related mortality. A score of 0-2 is considered low risk, 3-6 moderate risk and 7-12 high risk. 7 6