County-Level COVID-19 Vaccination Rates, Non-Communicable Diseases, and Socioeconomic Inequities: Applying Syndemic Theory to Vaccines

Introduction. The coronavirus disease 2019 (COVID-19) pandemic has dispro-portionately affected certain high -risk populations, including those with underlying chronic illnesses and those who are socioeconomically disadvantaged. Methods. Our study evalu-ated county -level rates of fully vaccinated populations after classifying counties based on rates of non-communicable diseases (NCDs) and socioeconomic inequities below the 25th percentile of overall distribution of counties for each measure as low, counties above the 75th percentile as high, and all other counties as medium. Results. Counties with higher rates of non-communicable diseases and socioeconomic disparities had lower COVID-19 vaccination coverage than did counties with lower rates of non-communicable diseases and socioeconomic disparities. Co-occurrence of high NCD and high socioeconomic vulner-ability among counties in the lower half of vaccination coverage was also found for some counties. Conclusion. These findings demonstrate the co-occurrence of low rates of vaccine coverage, high rates of NCDs, and high rates of socioeconomic disparities as a syndemic.