Sociodemographic and geographic disparities in COVID-19 booster vaccination in Nueces County, Texas, USA

Objective: This paper explores sociodemographic determinants and geographic disparities in COVID-19 booster uptake among fully vaccinated adults in Nueces County, Texas, USA with a population of over 353,000. Methods: A logistic generalized additive model was applied to analyze 184,252 official vaccination records of fully vaccinated adults over the period between December 2020 and August 2022. An individual's odds in receiving a booster shot were estimated with a host of sociodemographic characteristics as predictors. Results: Model estimation results reveal that male (odds ratio 0.836, 95% confidence interval 0.835–0.836, p < 0.001) and Hispanic residents (odds ratio 0.944, 95% confidence interval 0.943–0.945, p < 0.001) in the county were less likely to take a booster shot. Between the ages of 25 and 75, booster uptake increased with age (age 75 vs. 45 odd ratio 3.058, 95% confidence interval 3.052–3.063, p < 0.001). Booster uptake was lower in rural areas (odds ratio 0.804, 95% confidence interval 0.795–0.814, p < 0.001) and communities with high social vulnerability (highest vs. moderate vulnerability odd ratio 0.800, 95% confidence interval 0.767–0.836, p < 0.001). Conclusion: Empirical results confirm that booster uptake varied across individuals and communities of different socioeconomic and demographic characteristics. To advance health equity, a more inclusive vaccine campaign should pay particular attention to those underserved populations.