Decomposing racial/ethnic disparities in influenza vaccination among the elderly

Vaccine. 2015 Jun 12;33(26):2997-3002. doi: 10.1016/j.vaccine.2015.03.054. Epub 2015 Apr 18.


While persistent racial/ethnic disparities in influenza vaccination have been reported among the elderly, characteristics contributing to disparities are poorly understood. This study aimed to assess characteristics associated with racial/ethnic disparities in influenza vaccination using a nonlinear Oaxaca-Blinder decomposition method. We performed cross-sectional multivariable logistic regression analyses for which the dependent variable was self-reported receipt of influenza vaccine during the 2010-2011 season among community dwelling non-Hispanic African-American (AA), non-Hispanic White (W), English-speaking Hispanic (EH) and Spanish-speaking Hispanic (SH) elderly, enrolled in the 2011 Medicare Current Beneficiary Survey (MCBS) (un-weighted/weighted N=6,095/19.2 million). Using the nonlinear Oaxaca-Blinder decomposition method, we assessed the relative contribution of seventeen covariates - including socio-demographic characteristics, health status, insurance, access, preference regarding healthcare, and geographic regions - to disparities in influenza vaccination. Unadjusted racial/ethnic disparities in influenza vaccination were 14.1 percentage points (pp) (W-AA disparity, p<0.001), 25.7 pp (W-SH disparity, p<0.001) and 0.6 pp (W-EH disparity, p>.8). The Oaxaca-Blinder decomposition method estimated that the unadjusted W-AA and W-SH disparities in vaccination could be reduced by only 45% even if AA and SH groups become equivalent to Whites in all covariates in multivariable regression models. The remaining 55% of disparities were attributed to (a) racial/ethnic differences in the estimated coefficients (e.g., odds ratios) in the regression models and (b) characteristics not included in the regression models. Our analysis found that only about 45% of racial/ethnic disparities in influenza vaccination among the elderly could be reduced by equalizing recognized characteristics among racial/ethnic groups. Future studies are needed to identify additional modifiable characteristics causing disparities in influenza vaccination.

Keywords: Elderly population; Influenza vaccination; Non-linear Oaxaca–Blinder decomposition method; Racial/ethnic disparities.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Cross-Sectional Studies
  • Ethnic Groups*
  • Female
  • Health Services for the Aged*
  • Healthcare Disparities* / ethnology
  • Healthcare Disparities* / statistics & numerical data
  • Humans
  • Influenza Vaccines / administration & dosage*
  • Influenza, Human / prevention & control
  • Logistic Models
  • Middle Aged
  • Odds Ratio
  • Time Factors
  • Vaccination / statistics & numerical data*


  • Influenza Vaccines