1. Department of Population HealthLondon School of Hygiene and Tropical Medicine, London, UK
2. TAZAMA ProjectNational Institute for Medical Research, Mwanza, Tanzania
3. Department of Infectious Disease EpidemiologyLondon School of Hygiene and Tropical Medicine, London, UK
4. Medical Research Council/Uganda Virus Research Institute (MRC/UVRI), Research Unit on AIDS, Entebbe, Uganda
5. Karonga Prevention Study Chilumba, Malawi
6. Rakai Health Sciences Program, Uganda Virus Research Institute, Entebbe, Uganda
7. The Africa Centre for Health and Population StudiesUniversity of KwaZulu-Natal (UKZN), Somkhele, South Africa