Disparities in Influenza Vaccination of Chronically-ill US Adults: The Mediating Role of Perceived Discrimination in Healthcare

Despite well-established adult influenza vaccination programs, adult influenza vaccination rates in the US are well below federal benchmarks and exhibit well-documented, persistent racial and ethnic disparities. Understanding the contributors to vaccination disparities among chronically-ill adults is of particular importance since this population is at higher risk for influenza-related complications. The causes of disparities in influenza vaccination are multifactorial and complex, but perceived racial and ethnic discrimination in healthcare is one hypothesized mechanism. The objective of this study is to assess the role of perceived discrimination in healthcare in explaining racial/ethnic disparities in influenza vaccination. This study uses data collected from 2011-2012 from the AF4Q Consumer Survey, a nationally-representative survey of chronically-ill US adults focused on health and healthcare (n=9,572). It compares findings with the limited, mixed literature on the effects of discrimination on vaccination and it advances upon prior research by examining the role of discrimination as a mediator between race/ethnicity and influenza vaccination using binary mediation analysis. In unadjusted analyses, 59% of respondents with no experiences of perceived discrimination reported receiving the influenza vaccine compared to only 36% in those who had experienced discrimination (p=0.04). By race/ethnicity, 45% of non-Hispanic Blacks reported influenza vaccination compared to 57% of non-Hispanic Whites and 60% of Hispanics, though this was not a statistically significant disparity. Though the odds ratio of flu vaccination given perceived discrimination was not significant in the fully-adjusted model, the magnitude of the effect was fairly large and approached significance (OR 0.40, 95% CI: 0.15-1.10), and model fit (AIC and pseudo R²) improved when the discrimination variable was included. Perceived discrimination in healthcare significantly mediated about 17% of the unadjusted association between race/ethnicity and influenza vaccination, though this mediation dropped to 5% and the mediation coefficient lost statistical significance in the fully-adjusted model. The lack of statistical significance of the result may be due to sample size and sample weighting. The causes of persistent racial disparities in influenza vaccination are undoubtedly complex and a single explanation is unlikely to be sufficient. Current evidence elucidating discrimination and other mechanisms of racial/ethnic disparities is limited and this potential mediating pathway merits re-evaluation in a larger cohort.