1. Department of Science and Technology/National Research Foundation, Vaccine Preventable Diseases, and
2. Medical Research Council, Respiratory and Meningeal Pathogens Research Unit, University of the Witwatersrand, Johannesburg, South Africa;
3. Department of Pediatrics, Medicine and Pathology, University of Colorado Denver, Aurora;
4. Department of Medicine and Department of Global Health, University of Washington, Seattle;
5. Center for Vaccine Development, University of Maryland, Baltimore;
6. Department of Pediatrics, University of Colorado School of Medicine and Center for Global Health, Colorado School of Public Health, Aurora;
7. School of Pathology, University of the Witwatersrand, and
8. National Institute for Communicable Diseases, National Health Laboratory Service, Centre for Vaccines and Immunology, Johannesburg, South Africa