The Development of a Human Model of Respiratory Syncytial Virus Infection

The aim of this study is to understand the immune response (how the body fights infection) to Respiratory Syncytial Virus (RSV). This virus usually causes a simple 'common cold' illness in healthy adults, but can cause wheezing and lung problems in young infants and the elderly. The investigators want to understand why this is, in order to develop vaccines and treatments. Participants will include 30-40 healthy adults age 18-55 years. Study procedures will include brief medical exams, breathing tests, a diary of symptoms, blood tests, samples of fluid (lavage) and cells from the nose, throat and lungs. All participants will receive the virus via drops in the nose. The duration of the study for all subjects will be 6 weeks.