1. PATH, Center for Vaccine Innovation and Access, Geneva, Switzerland
2. PATH, Center for Vaccine Innovation and Access, Seattle, WA, USA
3. PATH, Center for Vaccine Innovation and Access, Washington, DC, USA
4. Faculté de Médecine, Université Libre de Bruxelles, Brussels, Belgium
5. Faculty of Public Health and Policy, Department of Health Services Research and Policy, London School of Hygiene and Tropical Medicine, London, UK