OBJECTIVES: To estimate the association between county-level social vulnerability and pneumococcal vaccine uptake among Medicare adult beneficiaries (≥65 years old) in the United States between 2016 and 2019.

METHODS: We calculated the county-level pneumococcal vaccine uptake among Medicare beneficiaries using 100% Medicare data available through the Chronic Conditions Data Warehouse Virtual Research Data Center. We identified pneumococcal vaccinations using the NDC (National Drug Code) and CPT (Current Procedural Terminology) codes for PPSV23 (Pneumovax 23) and PCV13 (Prevnar13) identified in the prescription drug claims, and procedure codes identified in outpatient and inpatient claims. Beneficiaries were considered vaccinated if they received at least one vaccine (PPSV23 or PCV13) during the study period. Counties were categorized into quintiles of area-level social disadvantage by the Minority Health Social Vulnerability Index (MHSVI) and its six subthemes (socioeconomic status, household characteristics, racial and ethnic minority status, housing type and transportation, health care infrastructure and access, and medical vulnerability).

RESULTS: Our study included a total of 56,909,953 Medicare members (2016-2019). When examining pneumococcal vaccine uptake by the overall MHSVI, we found that beneficiaries that live in the least vulnerable counties have higher vaccination rates than beneficiaries in the most vulnerable counties. We find a similar relationship for all subthemes of the SVI, except Racial and Ethnic Minority status. For this definition, we detected a statistically significant negative relationship between vulnerability and vaccination, meaning more-vulnerable areas had higher vaccination rates.

CONCLUSIONS: This study adds to the growing body of work describing health inequities. The findings suggest that the specific definition of area-level measure of vulnerability is critical in accurately estimating geographic disparities in pneumococcal vaccine uptake. Efforts to improve vaccination rates in socially vulnerable areas have the potential to decrease the clinical and economic burden of pneumococcal disease and improve public health.