title: System factors to explain H1N1 state vaccination rates for adults in US emergency response to pandemic.
abstract: BACKGROUND
  During the 2009-2010 H1N1 pandemic, vaccine in short supply was allocated to states pro rata by population, yet the vaccination rates of adults differed by state. States also differed in their campaign processes and decisions. Analyzing the campaign provides an opportunity to identify specific approaches that may result in higher vaccine uptake in a future event of this nature.
  
  
  OBJECTIVE
  To determine supply chain and system factors associated with higher state H1N1 vaccination coverage for adults in a system where vaccine was in short supply.
  
  
  METHODS
  Regression analysis of factors predicting state-specific H1N1 vaccination coverage in adults. Independent variables included state campaign information, demographics, preventive or health-seeking behavior, preparedness funding, providers, state characteristics, and H1N1-specific state data.
  
  
  RESULTS
  The best model explained the variation in state-specific adult vaccination coverage with an adjusted R-squared of 0.76. We found that higher H1N1 coverage of adults is associated with program aspects including shorter lead-times (i.e., the number of days between when doses were allocated to a state and were shipped, including the time for states to order the doses) and less vaccine directed to specialist locations. Higher vaccination coverage is also positively associated with the maximum number of ship-to locations, past seasonal influenza vaccination coverage, the percentage of women with a Pap smear, the percentage of the population that is Hispanic, and negatively associated with a long duration of the epidemic peak.
  
  
  CONCLUSIONS
  Long lead-times may be a function of system structure or of efficiency and may suggest monitoring or redesign of distribution processes. Sending vaccine to sites with broad access could be useful when covering a general population. Existing infrastructure may be reflected in the maximum number of ship-to locations, so strengthening routine influenza vaccination programs may help during emergency vaccinations also. Future research could continue to inform program decisions.
authors.affiliation: School of Industrial and Systems Engineering, Georgia Institute of Technology, 755 Ferst Drive, NW, Atlanta, GA 30332-0205, USA. Electronic address: carlo.davila@gatech.edu.
authors.forename: Carlo
authors.initials: C
authors.lastname: Davila-Payan
authors.affiliation: School of Industrial and Systems Engineering, Georgia Institute of Technology and School of Public Policy (by courtesy), Georgia Institute of Technology, 755 Ferst Drive, NW, Atlanta, GA 30332-0205, USA. Electronic address: jswann@isye.gatech.edu.
authors.forename: Julie
authors.initials: J
authors.lastname: Swann
authors.affiliation: Immunization Services Division, Centers for Disease Control and Prevention, CDC Corporate Square Building 8, Corporate Boulevard NE, Atlanta, GA 30329, USA. Electronic address: pmw1@cdc.gov.
authors.forename: Pascale M
authors.initials: PM
authors.lastname: Wortley
mesh_terms: D006801:Humans; D017589:Immunization Programs / Q000458:organization & administration*; D053118:Influenza A Virus, H1N1 Subtype; D007252:Influenza Vaccines / Q000008:administration & dosage / Q000600:supply & distribution*; D007251:Influenza, Human / Q000517:prevention & control*; D058873:Pandemics / Q000517:prevention & control; D012044:Regression Analysis; D014481:United States; D014611:Vaccination / Q000706:statistics & numerical data*
chemical_list: D007252:Influenza Vaccines
keywords: Adults; Coverage; Estimates; Factors; Pandemic; State-specific