COVID-19 Vaccine Coverage Index: Identifying barriers to COVID-19 vaccine uptake across U.S. counties

ImportanceThe United States is in a race against time to vaccinate its population to contain the COVID-19 pandemic. With limited resources, a proactive, targeted effort is needed to reach widespread community immunity. ObjectiveIdentify county-level barriers to achieving rapid COVID-19 vaccine coverage and validate the index against vaccine rollout data. DesignEcological study SettingPopulation-based ParticipantsLongitudinal COVID-19 vaccination coverage data for 50 states and the District of Columbia and 3118 counties from January 12 through May 25, 2021. Exposure(s)The COVID-19 Vaccine Coverage index (CVAC) ranks states and counties on barriers to coverage through 28 indicators across 5 themes: historic undervaccination, sociodemographic barriers, resource-constrained health system, healthcare accessibility barriers, and irregular care-seeking behaviors. A score of 0 indicates the lowest level of concern, whereas a score of 1 indicates the highest level of concern. Main Outcome(s) and Measure(s)State-level vaccine administrations from January 12 through May 25, 2021, provided by the Centers for Disease Control and Prevention (CDC) and Our World In Data. County-level vaccine coverage as of May 25, 2021, provided by the CDC. ResultsAs of May 25, 2021, the CVAC strongly correlated with the percentage of population fully vaccinated against COVID-19 by county (r = -0.39, p=2.2x10-16) and state (r=-0.77, p=4.9x10-11). Low-concern states and counties have fully vaccinated 26.5% [t=6.8, p=1.7x10-7] and 26% (t=22.0, p=2.2x10-16) more people, respectively, compared to their high-concern counterparts. This vaccination gap is at its highest point since the start of vaccination and continues to grow. Higher concern on each of the five themes predicts a lower rate of vaccination at the county level (all p<.001). We identify five types of counties with distinct barrier profiles. Conclusions and RelevanceThe CVAC measures underlying barriers to vaccination and is strongly associated with the speed of rollout. As the coverage gap between high- and low-concern regions continues to grow, the CVAC can inform a precision public health response targeted to underlying barriers. Key PointsO_ST_ABSQuestionC_ST_ABSWhich U.S. counties face barriers to COVID-19 vaccine rollout, and are these communities vaccinating fewer individuals? FindingsThe COVID-19 Vaccine Coverage Index (CVAC) comprises five themes reflecting county-level concern for low coverage. We report rural, regional, and racial divides in exposure to these vaccination barriers. The top third of states and counties of highest concern have vaccinated 19% and 20% fewer people, respectively, compared to regions of least concern. MeaningThe CVAC can help contextualize progress to widespread COVID-19 vaccine coverage, identifying underlying community-level factors that could be driving suboptimal rollout to inform precision solutions.