1 Global Health, Policy and Innovation Unit, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London E1 2AB, UK s.steele@qmul.ac.uk.
2 Global Health, Policy and Innovation Unit, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London E1 2AB, UK Richford Gate Medical Practice, Richford Street, London W67HY, UK.
3 Lifespan, 167 Point Street, Providence, Rhode Island 02903, USA.
4 National Clinical Guideline Centre, Royal College of Physicians, London NW1 4LE, UK.