Disparities in Preventive Care Utilization at the Intersection of Socioeconomic and Demographic Characteristics: A Survival Analysis of COVID-19 Vaccination Uptake in the United States.

Abstract

Context: Vaccination coverage against COVID-19 varied across populations. While previous studies primarily documented disparities at a point of time, how uptake rates evolved over time across categories of socioeconomic status (SES) is less visited.

Objective: This study utilizing timing (month and year) of the first dose of COVID-19 vaccination, assessed the differences in vaccination progress by different categories of SES across demographic groups in the United States (US).

Design/setting/participants: Using data from the 2022 Behavioral Risk Factor Surveillance System for 135 730 individuals aged 18+ years, living in 29 US states, we estimated Kaplan-Meier failure functions and stratified Cox proportional hazard models for the event of first vaccination.

Main outcome measures: We assessed how monthly survival probabilities, from December 2020 to December 2022, varied across categories of SES represented by educational attainment and household income in the full sample and in sub-samples of demographic characteristics including age groups, sex, and race and ethnicity.

Results: Estimates of the K-M failure functions suggested a SES gradient of COVID-19 vaccination uptake rates, which were highest among adults with a college degree and income of ≥400% of Federal Poverty Level (FPL), and lowest among adults with educational attainment of less than high school diploma and income of <100% of FPL. Compared to college graduates, adults without a high school diploma were 0.50 (95% confidence interval: 0.48-0.52) times, and compared to adults with income of ≥400% of FPL, adults with income of <100% of FPL were 0.60 times as likely to receive the first dose of vaccination. The hazard ratios of vaccination were 0.61 and 0.70 for adults with high school diploma and some college education, and 0.69 and 0.80 for adults with income of 100% to 199% and 200% to 399% of FPL, respectively. The differences between high and low SES categories were qualitatively similar, though differed by magnitudes across the demographic groups.

Conclusions: Our findings highlight a significant difference in the trends of COVID-19 vaccination uptake between individuals from high and low SES backgrounds and may offer insights for designing policies aimed at equitable vaccination coverage.