title: Demographic characteristics of members of the Vaccine Safety Datalink (VSD): A comparison with the United States population.
abstract: BACKGROUND
  The Vaccine Safety Datalink (VSD) is a collaboration between CDC and nine integrated health care systems that serves as a cornerstone of US post-licensure vaccine safety monitoring. Given concerns that potential differences between the insured VSD population and the US population could limit the generalizability of VSD study findings, we performed a comparison of the demographic characteristics between the two populations.
  
  
  METHODS
  We collected data from medical records and administrative files at VSD sites in 2010 to compare sex, age, race, ethnicity, income, and educational attainment to the 2010 US Census population. We also compared data on the 2012 VSD Medicaid population to 2012 US Medicaid data.
  
  
  RESULTS
  The VSD population included over eight million individuals in 2010, which represented 2.6% of the total US population. All major demographic groups were represented in the VSD. We found no major differences in comparing sex, race, ethnicity, and educational attainment between the VSD and the US population. Middle income populations were comparable between the VSD and the US. While the percentage of lower income populations was less in the VSD compared to the US, the VSD had over two million individuals in this group. Additionally, there were over 600,000 Medicaid members in the VSD in 2012, which represented 1.1% of the US Medicaid population.
  
  
  CONCLUSIONS
  We found that the VSD population is representative of the general US population on several key demographic and socioeconomic variables. Despite a few specific groups being underrepresented in the VSD compared to the US, the absolute number of VSD members is large enough to ensure significant representation of these groups in vaccine safety studies that use VSD data.
authors.affiliation: Immunization Safety Office, Centers for Disease Control and Prevention, Atlanta, Georgia; Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia. Electronic address: xfq3@cdc.gov.
authors.forename: Lakshmi
authors.initials: L
authors.lastname: Sukumaran
authors.affiliation: Immunization Safety Office, Centers for Disease Control and Prevention, Atlanta, Georgia.
authors.forename: Natalie L
authors.initials: NL
authors.lastname: McCarthy
authors.affiliation: Immunization Safety Office, Centers for Disease Control and Prevention, Atlanta, Georgia.
authors.forename: Rongxia
authors.initials: R
authors.lastname: Li
authors.affiliation: Immunization Safety Office, Centers for Disease Control and Prevention, Atlanta, Georgia.
authors.forename: Eric S
authors.initials: ES
authors.lastname: Weintraub
authors.affiliation: Department of Research and Evaluation, Kaiser Permanente of Southern California, Pasadena, California, USA.
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Jacobsen
authors.affiliation: Department of Ambulatory Care Services, Denver Health, Institute for Health Research, Kaiser Permanente Colorado, Department of Pediatrics, University of Colorado, Denver, Colorado, USA.
authors.forename: Simon J
authors.initials: SJ
authors.lastname: Hambidge
authors.affiliation: Group Health Research Institute, Seattle, Washington, USA.
authors.forename: Lisa A
authors.initials: LA
authors.lastname: Jackson
authors.affiliation: The Center for Health Research, Kaiser Permanente Northwest, Portland, Oregon, USA.
authors.forename: Allison L
authors.initials: AL
authors.lastname: Naleway
authors.affiliation: Kaiser Permanente Vaccine Study Center, Oakland, California, USA.
authors.forename: Berwick
authors.initials: B
authors.lastname: Chan
authors.affiliation: Immunization Safety Office, Centers for Disease Control and Prevention, Atlanta, Georgia.
authors.forename: Biwen
authors.initials: B
authors.lastname: Tao
authors.affiliation: Immunization Safety Office, Centers for Disease Control and Prevention, Atlanta, Georgia.
authors.forename: Julianne
authors.initials: J
authors.lastname: Gee
mesh_terms: D000293:Adolescent; D000328:Adult; D016907:Adverse Drug Reaction Reporting Systems; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D016208:Databases, Factual; D003710:Demography; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D011358:Product Surveillance, Postmarketing; D014481:United States; D014612:Vaccines / Q000008:administration & dosage* / Q000009:adverse effects*; D055815:Young Adult
chemical_list: D014612:Vaccines
keywords: Census; Demographics; Medicaid; Vaccine Safety Datalink