1. School of Social and Community Medicine, University of Bristol, Bristol, UK (JM, AEA, MP, NJW)
2. Department of Medicine, Imperial College, London, UK (KM)
3. KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya (KM, JJ)
4. Centre for Health Economics, University of York, York, UK (PR)
5. Warwick Medical School, University of Warwick, Coventry, UK (JM)