Long-term therapy with aerosolized ribavirin for parainfluenza 3 virus respiratory tract infection in an infant with severe combined immunodeficiency Severe combined immunodeficiency syndrome is a rare group of genetic disorders characterized by a primary deficiency of T-, B-, and NK cell- mediated immunity (1). Allogeneic HSCT is the only treatment commonly available for SCID (2, 3). Success rates depend on donor compatibility with recipient and, importantly, the infection status of the child at the time of transplant. Event-free survival varies between 50% and 90% provided the procedure is performed within the first months of life (4). Notably, infants in poor physical condition, especially those with lung damage from infection, fare much worse with a survival of <30% (4). Because of impaired immunity, viral RTIs are major causes of morbidity and mortality in children with SCID and in recipients of HSCT (5–7). PIV3 is a single stranded-enveloped RNA virus that is often associated with persistent and progressive lower respiratory tract disease and fatal outcomes in immunocompromized patients (8, 9). We report the case of a child with SCID and PIV3 infection treated continuously for 10 months with aerosolized ribavirin (Virazole; ICN Pharmaceuticals, Costa Mesa, CA, USA). Prolonged administration in this child did not result in short- or long-term side effects for the patient or the medical staff during the three years following the treatment completion. Ribavirin Stankova J, Carret A-S, Moore D, McCusker C, Mitchell D, Davis M, Mazer B, Jabado N. Long-term therapy with aerosolized ribavirin for parainfluenza 3 virus respiratory tract infection in an infant with severe combined immunodeficiency. Pediatr Transplantation 2007: 11: 209–213. Ó 2007 Blackwell Munksgaard Abstract: We report the case of an infant with severe combined immunodeficiency who was presented with PIV3 infection. Aerosolized ribavirin was administered for 10 months until the child gained a functional immune system through an allogeneic hematopoietic stem cell transplant and cleared PIV3 infection. No adverse effect was ob- served in the child and in healthcare personnel, with a follow-up of three years. Despite the burden of aerosolized administration, early and prolonged administration of aerosolized ribavirin was feasible, well tolerated, and safe for the patient and the caregivers. This is a case report and no definite conclusions can be drawn. However, our experience suggests that prolonged aerosolized ribavirin administration should be considered for the treatment of PIV3 infection in the context of primary immunodeficiency, where there is no currently available alternative treatment, until a functional immune system is gained. Jitka Stankova 1 *, Anne-Sophie Carret 1 *, Dorothy Moore 2 , Christine McCusker 3 , David Mitchell 1 , Michael Davis 4 , Bruce Mazer 3 and Nada Jabado 1 1 Division of Hematology and Oncology, 2 Division of Infectious Diseases, 3 Division of Allergy and Immunology, 4 Division of Respiratory Medicine, Montreal Children's Hospital, McGill University Health Centre, Montreal, QC, Canada Key words: severe combined immunodeficiency syndrome – parainfluenza 3 – ribavirin – aerosolized – stem cell transplantation Nada Jabado, Montreal Children's Hospital Research Institute, 4060 Ste Catherine West, PT-239, Montreal, QC H3Z 2Z3, Canada Tel.: +1 514 412 4400 23270 Fax: +1 514 412 4331 E-mail: nada.jabado@mcgill.ca *These authors contributed equally to this work. Accepted for publication 31 July 2006 Abbreviations: CT, computed tomography; GTP, guanosine triphosphate; HLA, histocompatibility locus antigen; HSCT, hematopoietic stem cell transplantation; NK, natural killer; NPA, nasopharyngeal aspirates; PIV3, para- influenza virus type 3; RSV, respiratory syncytial virus; RTI, respiratory tract infections; SCID, severe combined immunodeficiency syndrome; URTI, upper respiratory tract infection. Pediatr Transplantation 2007: 11: 209–213. Copyright Ó 2007 Blackwell Munksgaard Pediatric Transplantation DOI: 10.1111/j.1399-3046.2006.00607.x 209