1. a London School of Hygiene & Tropical Medicine , London , UK
2. b National Institute for Medical Research , Tanzania
3. c Reproductive Health and HIV Research Unit , University of the Witwatersrand , South Africa
4. d HIV Prevention Research Unit, Medical Research Council , South Africa
5. e Medical Research Council , UVRI Uganda research unit on AIDS , Masaka , Uganda
6. f Microbicides Development Programme , Zambia
7. g Barcelona Centre for International Health Research , University of Barcelona , Spain