Study Identifies Social Factors Associated with Receipt of Influenza Vaccine

Influenza vaccination rates in the United States are below the Healthy People 2020 goal, so researchers assessed the impact of social determinants of health on adherence to annual influenza vaccination in U.S. adults. The researchers found that key social determinants of health are important factors of vaccine adherence and can guide policy and intervention efforts toward addressing potential hesitancy.

The results of the study were presented during AMCP Nexus 2020 Virtual in a poster presentation titled “The Role of Social Determinants of Health in Adult Influenza Vaccination: A Nationwide Claims Analysis.”

Researchers conducted a retrospective cohort analysis using IBM MarketScan commercial claims and 5% Medicare databases. The study included 7,816,421 U.S. adults who were continuously enrolled in employer-sponsored, Medicare Advantage, or traditional fee-for-service Medicare coverage between 2013 and 2016. Receipt of the influenza vaccine was counted over three consecutive influenza seasons and select social determinants were extracted from publicly available sources and linked by voting records, poverty, health literacy, and internet access. Patient characteristics, health resource utilization, and social determinants of health were included in bivariate and logistic regression analyses to determine their association with receipt of annual vaccination.

Among the cohort, just 9.2% of participants received an influenza vaccine in all three seasons tracked. Higher proportions of vaccine adherence (i.e., all three seasons) were observed in women (9.6%), the immunocompromised (10.8%), rural residents (9.9%) (P<0.0001 for all), and those enrolled in a high-deductible health plan (10.3%). A majority (63.9%) of commercially insured adults were unvaccinated across all three years.

Multivariable models indicated the odds of vaccinating in all three years were somewhat more likely in areas of higher health literacy (adjusted odds ratio [aOR], 1.035; 95% confidence interval [CI], 1.035-1.036), in individuals with more prescription fills (aOR, 1.006; 95% CI, 1.006-1.006), in communities with lower rates of internet access (aOR, 1.011; 95% CI, 1.010-1.013), and among those who did not relocate during the observation period (aOR, 1.05; 95% CI, 1.035-1.060). Slightly lower odds were observed in more liberal voting areas (aOR, 0.998; 95% CI, 0.997-0.999).

“A deeper assessment of other contributing social factors is needed in seasonal influenza and other vaccines to better interpret the vaccine-seeking behaviors of adults,” researchers concluded.

Gatwood J, Ramachandran S, Behal M, Hohmeier K, Hagemann T, Chiu CY. The Role of Social Determinants of Health in Adult Influenza Vaccination: A Nationwide Claims Analysis. Poster J2. AMCP Nexus 2020 Virtual.