title: Landscaping the structures of GAVI country vaccine supply chains and testing the effects of radical redesign.
abstract: BACKGROUND
  Many of the world's vaccine supply chains do not adequately provide vaccines, prompting several questions: how are vaccine supply chains currently structured, are these structures closely tailored to individual countries, and should these supply chains be radically redesigned?
  
  
  METHODS
  We segmented the 57 GAVI-eligible countries' vaccine supply chains based on their structure/morphology, analyzed whether these segments correlated with differences in country characteristics, and then utilized HERMES to develop a detailed simulation model of three sample countries' supply chains and explore the cost and impact of various alternative structures.
  
  
  RESULTS
  The majority of supply chains (34 of 57) consist of four levels, despite serving a wide diversity of geographical areas and population sizes. These four-level supply chains loosely fall into three clusters [(1) 18 countries relatively more bottom-heavy, i.e., many more storage locations lower in the supply chain, (2) seven with relatively more storage locations in both top and lower levels, and (3) nine comparatively more top-heavy] which do not correlate closely with any of the country characteristics considered. For all three cluster types, our HERMES modeling found that simplified systems (a central location shipping directly to immunization locations with a limited number of Hubs in between) resulted in lower operating costs.
  
  
  CONCLUSIONS
  A standard four-tier design template may have been followed for most countries and raises the possibility that simpler and more tailored designs may be warranted.
authors.affiliation: International Vaccine Access Center (IVAC), Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States; Public Health Computational and Operations Research (PHICOR), Pittsburgh, PA (formerly) and Baltimore, MD (currently), United States(1). Electronic address: brucelee@jhu.edu.
authors.forename: Bruce Y
authors.initials: BY
authors.lastname: Lee
authors.affiliation: Public Health Computational and Operations Research (PHICOR), Pittsburgh, PA (formerly) and Baltimore, MD (currently), United States(1).
authors.forename: Diana L
authors.initials: DL
authors.lastname: Connor
authors.affiliation: Public Health Computational and Operations Research (PHICOR), Pittsburgh, PA (formerly) and Baltimore, MD (currently), United States(1).
authors.forename: Angela R
authors.initials: AR
authors.lastname: Wateska
authors.affiliation: Department of Industrial Engineering, University of Pittsburgh, Pittsburgh, PA, United States.
authors.forename: Bryan A
authors.initials: BA
authors.lastname: Norman
authors.affiliation: Department of Industrial Engineering, University of Pittsburgh, Pittsburgh, PA, United States.
authors.forename: Jayant
authors.initials: J
authors.lastname: Rajgopal
authors.affiliation: Public Health Computational and Operations Research (PHICOR), Pittsburgh, PA (formerly) and Baltimore, MD (currently), United States(1).
authors.forename: Brigid E
authors.initials: BE
authors.lastname: Cakouros
authors.affiliation: Department of Industrial Engineering, University of Pittsburgh, Pittsburgh, PA, United States.
authors.forename: Sheng-I
authors.initials: SI
authors.lastname: Chen
authors.affiliation: Department of Industrial Engineering, University of Pittsburgh, Pittsburgh, PA, United States.
authors.forename: Erin G
authors.initials: EG
authors.lastname: Claypool
authors.affiliation: Public Health Computational and Operations Research (PHICOR), Pittsburgh, PA (formerly) and Baltimore, MD (currently), United States(1); Pittsburgh Supercomputing Center (PSC), Carnegie Mellon University, Pittsburgh, PA, United States.
authors.forename: Leila A
authors.initials: LA
authors.lastname: Haidari
authors.affiliation: Public Health Computational and Operations Research (PHICOR), Pittsburgh, PA (formerly) and Baltimore, MD (currently), United States(1).
authors.forename: Veena
authors.initials: V
authors.lastname: Karir
authors.affiliation: Department of Industrial Engineering, University of Pittsburgh, Pittsburgh, PA, United States.
authors.forename: Jim
authors.initials: J
authors.lastname: Leonard
authors.affiliation: Public Health Computational and Operations Research (PHICOR), Pittsburgh, PA (formerly) and Baltimore, MD (currently), United States(1).
authors.forename: Leslie E
authors.initials: LE
authors.lastname: Mueller
authors.affiliation: Public Health Computational and Operations Research (PHICOR), Pittsburgh, PA (formerly) and Baltimore, MD (currently), United States(1).
authors.forename: Proma
authors.initials: P
authors.lastname: Paul
authors.affiliation: Public Health Computational and Operations Research (PHICOR), Pittsburgh, PA (formerly) and Baltimore, MD (currently), United States(1).
authors.forename: Michelle M
authors.initials: MM
authors.lastname: Schmitz
authors.affiliation: Pittsburgh Supercomputing Center (PSC), Carnegie Mellon University, Pittsburgh, PA, United States.
authors.forename: Joel S
authors.initials: JS
authors.lastname: Welling
authors.affiliation: Public Health Computational and Operations Research (PHICOR), Pittsburgh, PA (formerly) and Baltimore, MD (currently), United States(1).
authors.forename: Yu-Ting
authors.initials: YT
authors.lastname: Weng
authors.affiliation: Pittsburgh Supercomputing Center (PSC), Carnegie Mellon University, Pittsburgh, PA, United States.
authors.forename: Shawn T
authors.initials: ST
authors.lastname: Brown
mesh_terms: D004356:Drug Storage / Q000191:economics / Q000379:methods*; D006297:Health Services Accessibility / Q000191:economics / Q000458:organization & administration*; D006801:Humans; D014612:Vaccines / Q000191:economics / Q000600:supply & distribution*
chemical_list: D014612:Vaccines
keywords: Immunization; Modeling; Supply chains