1. Centre for Academic Primary Care, Department of Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
2. Primary Care and Population Sciences, University of Southampton, Southampton, UK
3. Bristol Randomised Trials Collaboration, Department of Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
4. School of Population Health and Environmental Sciences, Faculty of Life Sciences and Medicine, King’s College London, London, UK
5. Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, London, UK
6. Julius Center for Health Sciences and Primary Care & Department of Otorhinolaryngology, UMC Utrecht, Utrecht, the Netherlands
7. Department of Medical Microbiology, North Bristol NHS Trust, Bristol, UK
8. Ear Institute, University College London, London, UK
9. School of Medicine, University of Sunderland, Sunderland, UK