1. Department of Global Health, University College London, London, UK
2. MRC Tropical Epidemiology Group, London School of Hygiene and Tropical Medicine, London, UK
3. Centre for Sexual Health HIV/AIDS Research (CeSHHAR), Harare, Zimbabwe
4. World Education Inc./Bantwana (WEI/B), Harare, Zimbabwe
5. Department of International Public Health, Liverpool School of Tropical Medicine, Liverpool, UK