1. Africa Centre for Population Studies and Reproductive Health and Departments of Medical Microbiology, University of Natal, Durban, South Africa
2. South Australian Centre for Rural and Remote Health, Adelaide University and University of South Australia, Whyalla and Adelaide, Australia
3. Biostatistics Unit, Medical Research Council, Durban, South Africa
4. Obstetrics and Gynaecology, Nelson R. Mandela School of Medicine, University of Natal, Durban, South Africa