1. Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, Washington, USA
2. Department of Medicine, University of Washington, Seattle, Washington, USA
3. Department of Microbiology, University of Washington, Seattle, Washington, USA
4. Department of Laboratory Medicine, University of Washington, Seattle, Washington, USA
5. Department of Epidemiology, University of Washington, Seattle, Washington, USA
6. Fred Hutchinson Cancer Research Center, Vaccine and Infectious Disease Institute, Seattle, Washington, USA
7. Department of Molecular Medicine and Haematology, University of Witwatersrand, Johannesburg, South Africa
8. Contract Laboratory Services, University of Witwatersrand, Johannesburg, South Africa
9. Perinatal HIV Research Unit, University of the Witwatersrand, Johannesburg, South Africa
10. Department of Global Health, University of Washington, Seattle, Washington, USA
11. Reproductive Health & HIV Research Unit, University of the Witwatersrand, Johannesburg, South Africa
12. Department of Pediatrics, University of Washington, Seattle, Washington, USA