Geographical Analysis of Malaria and HIV in Malawi

Project Summary

UNC Project-Malawi is collaborating with GlaxoSmithKline (GSK) on a malaria vaccine trial that will measure the efficacy of the GSK Biologicals’ candidate malaria vaccine (RTS,S/AS01E) against malaria disease caused by P. falciparum infection in infants and children in Africa. The study is a multi-center Phase III randomized double-blind trial that will be implemented across diverse malaria settings throughout Africa. UNC will implement the trial at the Lilongwe, Malawi, site. The Lilongwe trial will include 1300 children, half cases and the other half controls.

The primary goal of the trial is to measure the efficacy of the vaccine against clinical malaria; several secondary goals include measuring efficacy under different transmission settings. The trial includes diverse trial areas throughout Africa; between-site differences are supposed to represent the “different transmission settings.” Another possible way to measure differences in efficacy by transmission setting is with trials that investigate within-site variation, called “ecological vaccine trials.” For example, local-level ecological differences in vector habitat and household ecology can influence malaria transmission and therefore could affect efficacy. Furthermore, individuals visiting relatives in other regions of the country with different malaria prevalence rates might also affect local transmission. We will develop and implement ecological vaccine trial methods in the RTS,S/AS01E vaccine trial in Lilongwe. A geographic information system (GIS) database will be used to measure variation within study area.

Examples of spatial layers that would be relevant for such an ecological malaria vaccine trial include (a) population density, (b) proximity of households to standing water locations, (c) neighborhood-level household ecology (e.g., bed net usage), and d) mosquito trap data. People’s migration habits can also be considered by asking questions about where people have visited and incorporating that information into multi-level statistical models. Other medical geography studies that we are beginning to conduct in Malawi include an investigation of local-level patterns of HIV prevalence in Lilongwe.

Project Team Members

Michael Emch
Sophia Giebultowicz
Caryl Feldacker
Cameron Taylor

Funding

UNC Institute for Global Health and Infectious Diseases