Geospatial analytics to evaluate point-of-dispensing sites for mass immunizations in Allegheny County- Pennsylvania

CONTEXT: Public health agencies use mass immunization locations to quickly administer vaccines to protect a population against an epidemic. The selection of such locations is frequently determined by available staffing levels and in some places- not all potential sites can be opened- often because of a lack of resources. Public health agencies need assistance in determining which n sites are the prime ones to open given available staff to minimize travel time and travel distance for those in the population who need to get to a site to receive treatment. OBJECTIVE: Employ geospatial analytical methods to identify the prime n locations from a predetermined set of potential locations (eg- schools) and determine which locations may not be able to achieve the throughput necessary to reach the herd immunity threshold based on varying R0 values. DESIGN: Spatial location-allocation algorithms were used to select the ideal n mass vaccination locations. SETTING: Allegheny County- Pennsylvania- served as the study area. MAIN OUTCOME MEASURES: The most favorable sites were selected and the number of individuals required to be vaccinated to achieve the herd immunity threshold for a given R0- ranging from 1.5 to 7- was determined. Locations that did not meet the Centers for Disease Control and Prevention throughput recommendation for smallpox were identified. RESULTS: At R0 = 1.5- all mass immunization locations met the required throughput to achieve the herd immunity threshold within 5 days. As R0s increased from 2 to 7- an increasing number of sites were inadequate to meet throughput requirements. CONCLUSIONS: Identifying the top n sites and categorizing those with throughput challenges allows health departments to adjust staffing- shift length- or the number of sites. This method has the potential to be expanded to select immunization locations under a number of additional scenarios.