1. Health Services Unit KEMRI Wellcome Trust Research Programme Nairobi Kenya
2. Department of Medical Statistics London School of Hygiene & Tropical Medicine London UK
3. Department of Population Health London School of Hygiene & Tropical Medicine London UK
4. Department of Epidemiology and Biostatistics Kilimanjaro Christian Medical University College Moshi Tanzania
5. Centre for Tropical Medicine and Global Health Nuffield Department of Medicine University of Oxford Oxford UK