[DUPLICATE] Geographic Information System and tools of spatial analysis in a pneumococcal vaccine trial.

BACKGROUND: The goal of this Geographic Information System (GIS) study was to obtain accurate information on the locations of study subjects- road network and services for research purposes so that the clinical outcomes of interest (e.g.- vaccine efficacy- burden of disease- nasopharyngeal colonization and its reduction) could be linked and analyzed at a distance from health centers- hospitals- doctors and other important services. The information on locations can be used to investigate more accurate crowdedness- herd immunity and/or transmission patterns. METHOD: A randomized- placebo-controlled- double-blind trial of an 11-valent pneumococcal conjugate vaccine (11PCV) was conducted in Bohol Province in central Philippines- from July 2000 to December 2004. We collected the information on the geographic location of the households (N = 13-208) of study subjects. We also collected a total of 1982 locations of health and other services in the six municipalities and a comprehensive GIS data over the road network