1. WorldPop, School of Geography and Environmental Science, University of Southampton, Southampton SO17 1BJ, UK
2. Department of Biostatistics, School of Public Health, College of Health Sciences, University of Ghana, Accra P.O. Box LG13, Ghana
3. School of Mathematical Sciences, University of Southampton, Southampton SO17 1BJ, UK
4. Sydani Group, Abuja, Nigeria
5. Gavi, The Vaccine Alliance, Abuja, Nigeria
6. National Bureau of Statistics, Abuja, Nigeria
7. Gavi, The Vaccine Alliance, Geneva, Switzerland
8. Department of Statistics, Nnamdi Azikiwe University, Awka PMB 5025, Nigeria