1. Department of Data and Analytics, World Health Organization, 20 Avenue Appia, 1211 Geneva, Switzerland
2. Department of Immunization, Vaccines, and Biologicals, World Health Organization, 20 Avenue Appia, 1211 Geneva, Switzerland
3. Global Immunization Division, US Centres for Disease Control and Prevention, Atlanta, GA 30329, USA
4. Measurement, Evaluation and Learning Department, Gavi, The Vaccine Alliance, 1218 Geneva, Switzerland