1. Department of Science and Technology/National Research Foundation, Vaccine Preventable Diseases & Medical Research Council, Respiratory and Meningeal Pathogens Research Unit, University of the Witwatersrand, Soweto, South Africa;
2. Centers for Disease Control and Prevention, Atlanta, Georgia;
3. Departments of Obstetrics and Gynaecology, and
4. Paediatrics, Division of Neonatology, Chris Hani Baragwanath Hospital, University of the Witwatersrand, Soweto, South Africa; and
5. National Institute for Communicable Diseases, National Health Laboratory Services, Sandringham, South Africa