An Epidemiologic Analysis of Associations between County-Level per Capita Income, Unemployment Rate, and COVID-19 Vaccination Rates in the United States

Background and Purpose: COVID-19 responsive community mitigation strategies (e.g., mandatory stay at home orders and business closures) were associated with an array of negative economic impacts, including higher unemployment rates and reductions in income. Individuals who are Black, Indigenous, People of Color (BIPOC) have been disproportionately affected by the economic impacts of COVID-19. Meanwhile, vaccination rates among BIPOC persons are lagging compared to their non-Hispanic White counterparts. However, social vulnerability is an aggregate score of all three factors which fails to allow for an examination of how unemployment rates and income may impact racial disparities on COVID-19 vaccination rates. The purpose of this longitudinal study was to examine associations between per capita income, unemployment rates, and COVID-19 vaccination rates at the county-level across the United States (U.S.), as well as identify interaction effects between county-level per capita income, unemployment rates, and racial/ethnic composition on COVID-19 vaccination rates.

Methods: All counties in the U.S. that reported COVID-19 vaccination rates from January 2021 to July 2021 were included in this longitudinal study (n=2,857). In total, the present study analyzed 19,999 county-time waves. The dependent variable was county-level adult vaccination rate, defined as the percentage of twice vaccinated adults per county on the first day of each month. County-level racial/ethnic composition, unemployment rate, and per capita income as moderating variables were obtained from the U.S. Census Bureau. Gender, age, and education et al. were included as covariants. Pooled ordinary least squares (OLS) with fixed-effects were employed to longitudinally examine economic impacts on racial disparities on county-level COVID-19 vaccination rates.

Results: County-level per capita income (R²=0.001, p=0.00) and county-level unemployment (R²=0.413, p=0.00) rates were both positively associated with county-level COVID-19 vaccination rates across the U.S. However, the associations were divergent in the context of race/ethnicity. Significant interaction effects were found between unemployment rates and the percentage of racial minorities (R²= -0.0009, p=0.00), as well as between unemployment rate and percentage of racial minorities (R²=0.737, p=0.00). In counties with greater racial minority populations, increases in per capita income were associated with lower vaccination rates; however, in counties with lower racial minority populations, increases in per capita income were associated with higher vaccination rates. In counties with greater racial minority populations, increases in unemployment rates were related to higher COVID-19 vaccination rates; however, in counties with lower racial minority populations, increases in unemployment rates were related to lower COVID-19 vaccination rates.

Conclusions: Our findings indicate that county-level per capita income is negatively associated with county-level COVID-19 vaccination rates in counties with higher proportions of BIPOC individuals, while county-level unemployment rate is negatively associated with county-level vaccination rates in counties with higher proportions of non-Hispanic White individuals. Taken together, it is critical to develop policy interventions to increase vaccination rates in racial minority communities in order to stimulate economic recovery. Public health efforts to bolster COVID-19 vaccination rates are encouraged to consider and respond to economic factors that are associated with decreases in COVID-19 vaccination rates.