Vaccine Modeling Initiative

The Bill & Melinda Gates Foundation has awarded a $10 million grant to the University of Pittsburgh Graduate School of Public Health and its partners at the Pennsylvania State's Center for Infectious Disease Dynamics and Imperial College London to create computational models and simulations that will help guide the development of new vaccine technologies and epidemic control strategies to stop the spread of infectious diseases.

The GeoVISTA Center's role is focusing on one of the study cases: Measles in Niger.

Study Site

Niger, one of the poorest and least developed countries in the world, lies in sub-Saharan Africa. It is mainly covered by the Sahara desert (> 80%) and is continually threatened by desertification and periodic droughts. Northern Niger is sparsely populated with much of the population residing in the tropical region along the southern border with Nigeria. Niger has a population estimate of 15,306,252 (CIA 2009) with one of the highest birth rates in the world (51.6 births per 1000 population). Although known for its mining (uranium), much of the economy in Niger is subsistence with some agricultural exports.

Niger has had difficulty controlling the spread of many diseases some of which have long been eradicated in developed countries (such as polio) , owing to the combination of an extremely high birth rate, minimal funding for government services, and a history of political struggles and insurgency since gaining independence in 1960. Measles, in particular, has attracted international cooperation from aid groups including the World Health Organization (WHO), UNICEF, the American Red Cross, the United Nations Foundation, and the U.S. Centers for Disease Control. All of whom contributed to efforts to control the spread of the disease through the Measles Initiative in 2001 (Ferrari, Grais et al. 2008). The Measles Initiative set a goal of reducing the incidence of measles by 90% by 2010, and following its implementation of increased vaccination coverage in 2004/2005, measles infections in Niger fell from 40,000 cases annually in 2003 to 476 in 2006 (UNICEF 2008), demonstrating the effectiveness of targeted, aggressive administration of inexpensive vaccines.

GeoVISTA's role in this project

In order to continue to effectively target vaccination programs in countries like Niger it is important to understand the spatial dynamics of the disease, specifically to understand patterns of disease movement both in space and time. Thus, we at GeoVISTA are providing expertise in geospatial visual analytics, geospatial analysis and geographic data gathering to:

  • Support investigation of the occurrence of disease in space and time through novel application of visualization methods, particularly through interactive map animation. One part of this work is focused on advancing knowledge about the impacts of map representation form (choropleth versus schematic maps) and data aggregation/smoothing on patterns that can be identified. See Craig McCabe's Thesis work.
  • Improve knowledge of patterns of human movement by looking at a variety of causal factors that may result in migration of people between locations in Niger as well as between locations in Niger and its surrounding countries. To accomplish this we we developed new information seeking methods that allow analysts to forage a variety of text documents on the web (e.g. from news archives), generate relevance rankings, and explore the place, time, and concept components of the documents through linked map, timeline, concept map, and documents views. See: Tomaszewski B, Blanford J, Ross KS, Pezanowski S, MacEachren AM. (2011) Supporting Rapid Sense Making in Diverse Web Document Foraging. Computers, Environment and Urban Systems. 35:192-207.
  • Improve our understanding of accessibility throughout Niger to help (a) determine how to deliver vaccines more effectively - that is when/whether to take the vaccine to the people or try to get the people to the vaccine, and (b) determine who has access to health facilities by looking at how accessible current facilities are to Nigeriens by investigating (i) how movement may be enhanced or restricted throughout the country using different modes of transportation (walking and vehicular) and (ii) at different times of the year (wet and dry season). See: Blanford, JI, Kumar, S, Wei, L, and MacEachren, AM. (2012) It's a long, long walk: accessibility to hospitals, maternity and integrated health centers in Niger. International Journal of Health Geographics.

By exploring these we hope to improve our understanding of the patterns of human movement in Niger, which is not currently well documented, as well as improve access to health care. Achieving this will further aid modeling of disease dynamics in this region as well as in other developing countries.

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