RSV Study in Adults 60 to 75 Years of Age

Inclusion Criteria (non-exhaustive list): * Healthy subjects aged 60 to 75 years * Able to give informed consent * A total body weight ≥ 50 kg and Body Mass Index (BMI) ≥ 18 kg/m2 and ≤ 33 kg/m2. * In good health with no history of major medical conditions, or clinically significant test abnormalities that will interfere with subject safety as determined by the Investigator at screening evaluation * Documented medical history either prior to entering the study and/or following medical history review by the Investigator at screening. * Serum IgA result within normal range at screening. * Subjects meeting the contraception criteria of the study. Exclusion Criteria (non-exhaustive list): * Subjects who have smoked ≥ 10 pack years (or 20 cigarettes a day for 10 years). Of those subjects that have smoked less than 10 pack years at any time, a subject will be excluded, if in the last year, he/she has smoked any number of cigarettes in the last month and/or they have used tobacco in any form or other nicotine-containing products in any form. * Subjects who smoked in the last month prior to the study * Females who are breastfeeding, have been pregnant within 6 months prior to the study, or have a positive pregnancy test. * History of clinically significant or major disease that, in the opinion of the Investigator, may interfere with a subject completing the study and necessary investigations. * A forced expiratory volume in 1 second (FEV1) \< 80% predicted. * Twelve-lead ECG recording with clinically relevant abnormalities. * Positive HIV, Hep A, B or C test. * Confirmed positive test for drugs of abuse. * Presence of fever prior to the challenge. * Evidence of vaccinations within the 4 weeks prior to the planned date of enrolment, or intention to receive any vaccination before the last scheduled visit of the study. * Those employed or immediate relatives of those employed at hVIVO. * Receipt of blood or blood products, or loss (including blood donations) of 470 mL or more of blood during the 3 months prior to the planned date of enrolment. * Receipt of systemic glucocorticoids or systemic antiviral drugs within 6 months prior to the planned date of enrolment. * History or currently active symptoms suggestive of upper or lower respiratory tract infection within 6 weeks prior to enrolment. * Any clinically significant history of large nosebleeds. * Any significant abnormality altering the anatomy of the nose. * History of significant/severe wheeze, respiratory symptoms resulting in hospitalisation, or known bronchial hyperreactivity to viruses. * History of anaphylaxis-and/or severe allergic reaction. * Use or anticipated use during the conduct of the study of concomitant medications. * Resident of nursing home and other long-term care facilities or with close or household contact with vulnerable people for approximately 2 weeks following discharge from unit. * History or presence of alcohol addiction. * Any other finding that, in the opinion of the Investigator, deems the subject unsuitable for the study. * Subjects with no detectable antibody to the challenge virus.