Respiratory syncytial virus infections in hematopoietic stem cell transplant recipients and other severely immunocompromised patients

Respiratory syncytial virus (RSV), a single stranded RNA virus, causes yearly seasonal epidemics of upper and lower respiratory infections affecting, to various degrees, all age groups. In North America and Europe, these epidemics generally start in late October-early November, peak at the end of December through February, and then gradually fade away in the spring. It is well known that during these yearly epidemics RSV is the leading lower respiratory infection of children. By the time a child reaches 24 months of age, the chance of his or her having been infected with RSV is >95% [ 1]. Although less common than in children, RSV is also a pathogen of adults. Outbreaks in nursing homes have been well documented, with pneumonia developing in similar to 66% of patients [ 2]. Other groups of patients are at increased risk of severe RSV infections : those with underlying chronic lung diseases, congenital heart disease, prematurity, or those who are severely immunocompromised. RSV also is an increasingly well recognized and of ten fatal complication of patients undergoing hematopoietic stem cell transplantation. Case fatality ratios in this patient population have been reported to exceed 70% [ 3]. This paper explores RSV pathology and pathogenesis, epidemiology and outcome, diagnosis, treat ment, future studies, and recommendations.