In many settings, data is collected as case counts through passive surveillance systems. To transform the collected case counts to incidence measures, accurate estimates of the underlying population numbers are needed as a denominator. Generally, census numbers are used for this. However, censuses are conducted infrequently and provide therefore only a snapshot of the population distribution at a particular time. In reality, populations are highly mobile and large-scale seasonal population movements have been observed for many countries. These movements lead to seasonal changes in population density, meaning using static, census-derived denominators is likely to bias incidence estimates.
Mobile phone data can be used to quantify these seasonal changes in population distribution and provide updated and dynamic denominators to be used for calculating district-level disease incidence. In addition to improving incidence estimates, awareness of seasonal movements has the potential to increase the impact of interventions, such as vaccination campaigns or distributions of commodities like bednets.
Andy Tatem, Elisabeth zu Erbach-Schoenberg WorldPop, Geography and Environment University of Southampton
(023) 8059 2636
Namibia National Vector Borne Disease Control Program, MTC Namibia, Bill and Melinda Gates Foundation, Clinton Health Access Initiative
Deville et al (2014) Dynamic population mapping using mobile phone data, PNAS Tatem et al (2014) Integrating rapid risk mapping and mobile phone call record data for strategic malaria elimination planning, Malaria Journal