1. International Vaccine Access Center, Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland;
2. Division of Viral Diseases, National Center for Immunizations and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia;
3. Kenya Medical Research Institute–Wellcome Trust Research Programme, Kilifi;
4. Department of Pathology, University of Otago, and
5. Microbiology Unit, Canterbury Health Laboratories, Christchurch, New Zealand;
6. Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, United Kingdom