With the DRC’s last census having taken place in 1984, there was an urgent need for accurate and reliable population estimates that can be used to plan health service delivery, including vaccination interventions. To that end, the project produced bottom-up gridded population estimates.
The first stage of creating the estimates was a microcensus survey implemented by KSPH. The microcensus took place between March and April 2021, with enumerators visiting a sample of 1,596 clusters spread across 7 provinces. These survey data were combined with some 500 geospatial covariates to create government-endorsed bottom-up population estimates for Haut-Katanga, Haut-Lomami, Ituri, Kasaï, Kasaï-Oriental, Lomami, and Sud-Kivu. Once produced and validated, the basemaps and high-resolution gridded population estimates data were fed into Flowminder’s optimisation algorithm (which used the data to model optimal locations for vaccination sites) with the target of having nearly 100 percent of the population live within 3km of either a fixed or a mobile vaccination post. The data outputs were combined to produce maps and immunisation plans for each health area. These documents included a summary page with key indicators such as the total and target population of the health area (as well as number of fixed and advanced sessions sites); a microplanning map of the health area containing the fixed and advanced vaccination sites (indicated with colour codes); as well as more-detailed tables breaking down the information for each vaccination site (by minimum frequency, population to be covered, and villages covered).
The project produced the nationwide population mobility estimates using anonymised and aggregated mobile operator data (call detail records, CDRs) and data from the project’s phone survey. The responses from the survey also supported the analysis of the CDR data and improved understanding of how demographics and mobility vary among subscribers of different mobile network operators in the DRC; among subscribers in different regions; and among those who use their phones often versus those who do not. Completed in the first week of November 2021, the survey included respondents from all the country’s provinces and interviewed a total of 7,500 people.
At a project-related event in November 2021, 95 percent of health professionals in attendance indicated they found the mobility data to be useful for their vaccination services, as the indicators can help to provide insights into both gradual population trends and sudden population movements. This echoed feedback the project team received from data managers and health zones’ head doctors (medecins chefs de zones) during the user-consultation sessions held in June 2021.
Currently, outputs from the phone survey and the microcensus survey are being combined with geospatial data to develop a statistical model and produce mobility estimates that are adjusted to reduce representation and measurement biases inherent to working with CDR data. The mobility estimates will be made available to the Ministry of Health staff via DHIS2.