Association Between Socio-Political and Economic Factors and COVID-19 Vaccination Uptake: US-Mexico Border Study

The implementation of COVID-19 vaccination in the United States has revealed substantial disparities driven by geography, socioeconomic status, and political ideology. This study explores how these factors were associated with vaccination intake across 360 counties within four U.S.-Mexico border states with distinct socio-political traits. Using regression analysis and GIS mapping, it evaluates the effects of income, education, employment, age, race, ethnicity, occupation, metro status, border status, and political affiliation on first-dose, full vaccination, and booster rates. First-dose rates were found to be significantly higher in border counties (β = 11.184, p < 0.001) and metropolitan areas (β = 2.246, p = 0.040). Democratic population (β = 0.644, p < 0.001) and per capita income (β = 0.950, p = 0.002) were positively associated with the vaccination. Complete-dose vaccination showed significant results similar to those of the first-dose model. Booster was positively associated with Democratic affiliation (β = 0.206, p < 0.001), high school graduation level (β = 0.172, p = 0.007), and the proportion of individuals aged 65 plus (β = 0.484, p < 0.001). In contrast, it was negatively associated with unemployment rates (β = −0.410, p < 0.001). Race and ethnicity also were related to vaccination outcomes: A higher Black population share was linked to lower first-dose vaccination rates (β = −0.386, p < 0.001), whereas Native American population share was associated with increased vaccination. Booster intake increased with a higher Asian population (β = 0.383, p = 0.001) but slightly declined with a higher White population (β = −0.071, p = 0.019).