In this project we are responding to a request from the Global Polio Eradication Initiative (GPEI) and the Bill and Melinda Gates Foundation for support in providing GIS-based population estimates for acute flaccid paralysis (AFP) surveillance denominators for inaccessible areas in countries such as CAR, South Sudan, and other countries with active vaccination campaigns. This data aids outbreak response interventions, ongoing vaccination efforts and provides more robust certification data than was previously available.

We are undertaking population modelling and analysis, adopting tried and tested methods that we have designed and successfully implemented in many other settings, as well as designing new methods to improve efficiency and speed of update. Methods include: 

• Disaggregation of trusted administrative area unit estimates to grid square-based population counts and characteristics. 
• Estimation of population counts in areas of incomplete enumeration using data from full enumeration elsewhere. 
• Estimation of population counts nationally using microcensus, household survey listings and other forms of survey data containing full or partial enumerations. 

We are also providing dedicated modelling capacity to produce population estimates where required. 

In each case, the integration of data on migration patterns/flows, or accounting for such migrations, are considered on a country-by-country basis. Outputs include both ‘best’ estimates of population counts (broken down by demographics and characteristics where relevant and possible), and metrics of uncertainty around these estimates at small administrative/enumeration area or grid square level.  

Project outputs are supporting a wide range of other WorldPop projects (e.g. GRID3) and include:

• Subnational population estimates for various countries.
• Neighbourhood type mapping from building footprint data for GPEI priority countries.
• Population mobility analyses and reports based on mobile location history data.