Preventing respiratory syncytial virus (RSV) disease in children
I n 1957, a virus recovered from infants with lower respiratory tract illness (LRTI) was named respiratory syncytial virus (RSV) for its ability to form multinucleated cells (syncytia) in cell culture (1). Early epidemiologic studies in highincome countries described the spectrum of RSV disease, including pneumonia, bronchiolitis (a characteristic wheezing LRTI), otitis media (middle ear infection), and apnea (pauses in breathing) in very young infants. Later studies demonstrated that RSV infection causes substantial disease in young children globally and that the burden of RSV in high-income countries is only a small fraction of the global burden. There is an urgent and universal need to develop products to reduce child mortality and morbidity through prevention of RSV disease. Fortunately, substantial progress has been made in the development of several promising RSV vaccines and monoclonal antibodies (mAbs) to achieve this goal.