The Impact of Age on Adaptive Immunity in Adults Infected With Respiratory Syncytial Virus

Inclusion Criteria: * Healthy persons aged 60 to 75 years, able to give informed consent * Non smokers or ex-smokers with smokers with less than or equal to 5 pack years smoking history. * Spirometry within the normal range for age and height (+/- 15%) * FEV1/FVC \>70% pre-bronchodilator Exclusion Criteria: * Chronic respiratory disease (asthma, COPD, rhinitis, sinusitis) in adulthood * Inhaled bronchodilator or steroid use within the last 12 months * Habitual use of any medication or other product (prescription or over-the-counter) for symptoms of rhinitis or nasal congestion within the last 3 months * Acute upper respiratory infection (URI or sinusitis) in the past 6 weeks * Subjects with allergic symptoms present at baseline * Clinically relevant abnormality on chest X-ray * Those in close domestic contact (i.e. sharing a household with, caring for, or daily face to face contact) with children under 3 years, other elderly adults (\>65 years), immunosuppressed persons, or those with chronic respiratory disease * Subjects with known or suspected immune deficiency * Receipt of systemic glucocorticoids (in a dose ≥ 5 mg prednisone daily or equivalent) within one month, or any other cytotoxic or immunosuppressive drug within 6 months prior to challenge * Known IgA deficiency, immotile cilia syndrome, or Kartagener's syndrome * History of frequent nose bleeds * Any significant medical condition or prescribed drug deemed by the study doctor to make the participant unsuitable f…