1. Clinical Research Department, United Kingdom
2. Karolinska Institute and Karolinska University Hospital, Stockholm, Sweden
3. University of the Witwatersrand and Wits Reproductive Health and HIV Institute, Johannesburg, South Africa
4. Institut National de la Santé et de la Recherche Médicale and Université de Montpellier, France
5. Medical Research Council Tropical Epidemiology Group, London School of Hygiene and Tropical Medicine, United Kingdom