Integration of Spatial and Social Network Analysis in Vaccine Trials

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).

In 1985, a community-based individually-randomized oral cholera vaccine trial was conducted in Matlab, Bangladesh. Existing methods for measuring the effectiveness of this vaccine trial to the transmission of the disease are not robust. New methods for spatial analysis and social network analysis are needed to better understand the impact of vaccine trials and disease transmission. This project builds on earlier work that developed theory and methods for incorporating neighborhood-level variables into 'ecological vaccine trials'.

Dr. Michael Emch at the University of North Carolina at Chapel Hill will reanalyze the cholera vaccine trial data from the previous study using new measures of social and environmental connectivity developed with social network analysis software, a geographic information system (GIS), and satellite remote sensing technologies. These new measures will help determine: (1) how placebo incidence and protective efficacy (PE) vary within social networks; (2) how placebo incidence and PE vary spatially by different environmental contexts; and (3) how spatial, environmental, and social network information can be used simultaneously to assess the effectiveness of vaccines and disease risk. Four data sets, already collected by the investigators, will be used for in this study. These datasets include: (1) a large cholera vaccine trial database, (2) a comprehensive longitudinal demographic database from which the vaccine trial participants were selected, (3) an accurate household-level GIS database, and (4) high resolution Quickbird satellite imagery. Kinship ties between all households will be measured using a complete network design as well as environmental connectivity using satellite imagery and GIS techniques. These GIS and satellite databases, in conjunction with the demographic, social network, and vaccine datasets, will facilitate adding integrated spatial, environmental, and social components to this vaccine evaluation study. Reanalyzing the Matlab oral cholera vaccine trial using a spatial analytical framework and social and environmental connectivity measures can give new insight into vaccine effectiveness evaluation and disease transmission modeling. As a result, the theoretical and methodological issues addressed in this project will have important implications for future vaccine trials.

This study will reanalyze an existing cholera vaccine trial database using new measures of social and environmental connectivity developed with social network analysis software, a geographic information system (GIS), and satellite remote sensing technologies. These methods will help determine: (1) how placebo incidence and efficacy vary within social networks; (2) how placebo incidence and efficacy vary spatially by different environmental contexts; and (3) how spatial, environmental, and social network information can be used simultaneously to assess the effectiveness of vaccines.