1. Zimbabwe AIDS Prevention Project–University of Zimbabwe Department of Community Medicine, Harare
2. MRC Tropical Epidemiology Group, London School of Hygiene and Tropical Medicine, London, United Kingdom
3. University of Zimbabwe College of Health Sciences, Harare
4. King’s College London, Institute of Psychiatry, Psychology and Neuroscience, London, United Kingdom
5. London School of Hygiene and Tropical Medicine, London, United Kingdom