1. Nuffield Department of Primary Care Health Sciences, University of Oxford, Oxford OX2 6GG, UK
2. Royal College of General Practitioners, Research and Surveillance Centre, London NW1 2FB, UK
3. Seqirus Ltd., London SL6 8AA, UK
4. Department of Clinical and Experimental Medicine, University of Surrey, Guildford GU2 7XH, UK
5. Institute for Medical and Biomedical Education, St George’s University of London, London SW17 0RE, UK