1. Medical Research Council: Respiratory and Meningeal Pathogens Research Unit, Faculty of Health Sciences, University of the Witwatersrand, York Road, Parktown, 2193, South Africa.
2. National Research Foundation: SARCHI on Vaccine Preventable Diseases, University of the Witwatersrand, Johannesburg, South Africa.
3. Stat-Epi Associates, Inc., Ponte Verde Beach, United States of America (USA).
4. International Vaccine Access Center, Johns Hopkins Bloomberg School of Public Health, Baltimore, USA.
5. Centers for Disease Control and Prevention, Atlanta, USA.