1. AstraZeneca South San Francisco CA USA
2. AstraZeneca Gaithersburg MD USA
3. Department of Science and Technology/National Research Foundation: Vaccine Preventable Diseases Faculty of Health Sciences University of the Witwatersrand Johannesburg South Africa
4. Medical Research Council: Respiratory and Meningeal Pathogens Research Unit Faculty of Health Sciences University of the Witwatersrand Johannesburg South Africa