1. Respiratory and Meningeal Pathogens Research Unit/Medical Research Council, Johannesburg, South Africa
2. Division of Infectious Diseases and Hospital Epidemiology, Cantonal Hospital St. Gallen, St. Gallen, Switzerland
3. Pfizer Vaccine Research and Development, Pfizer Inc., Pearl River, New York, USA
4. National Institute for Communicable Diseases, Johannesburg, South Africa
5. Callahan Associates Inc., La Jolla, California, USA
6. Biotechnology Clinical Development Statistics, Pfizer Inc., Pearl River, New York, USA
7. Emerging Pathogens Laboratory, Fondation Mérieux, Lyon, France
8. Hubert Department of Global Health and Division of Infectious Diseases, Emory University, Atlanta, Georgia, USA