Lay summary
Bronchiectasis is a chronic, debilitating disease characterised by productive cough, airway inflammation and repeated respiratory infections. It disproportionately affects Maori and Pacific peoples in New Zealand. Oral bacterial vaccines have been shown to boost the immune system, enhancing the killing of important respiratory bacteria. A novel and superior route of administration is under the tongue, which leads to direct absorption of the vaccine and bypasses the problem of inactivation in the gut. It offers a potentially simple and non-antibiotic treatment option for the prevention of infective exacerbations in patients with bronchiectasis. This feasibility, randomised, placebo-controlled trial will evaluate the clinical effects of Bactek-R, a sublingual bacterial vaccine. The potential benefits include fewer exacerbations, improved quality of life and reduced healthcare costs. This study will also investigate the lung microbiome, analysing bacteria found in the airways of bronchiectasis patients.