Impact of healthcare capacity disparities on the COVID-19 vaccination coverage in the United States: A cross-sectional study

Abstract

Background The impact of the COVID-19 vaccination campaign in the US has been hampered by a substantial geographical heterogeneity of the vaccination coverage. Several studies have proposed vaccination hesitancy as a key driver of the vaccination uptake disparities. However, the impact of other important structural determinants such as local disparities in healthcare capacity is virtually unknown. Methods In this cross-sectional study, we conducted causal inference and geospatial analyses to estimate the impact of healthcare capacity on the vaccination coverage disparity in the US. We evaluated the causal relationship between the healthcare system capacity of 2,417 US counties and their COVID-19 vaccination rate. We also conducted geospatial analyses using spatial scan statistics to identify areas with low vaccination rates. Findings We found a positive association between the healthcare capacity of a county and vaccination uptake. We estimated that a 1% increase in the Resource-Constrained Health System Index of a county increases by 0.37% the occurrence of that county in the set of counties classified as low-vaccinated (≤50% vaccination rate). We also found that COVID-19 vaccinations in the US exhibit a distinct spatial structure with defined vaccination coldspots. Interpretation We found that the healthcare capacity of a county is an important determinant of low vaccine uptake. Our study highlights that even in high-income nations, internal disparities in healthcare capacity play an important role in the health outcomes of the nation. Therefore, strengthening the funding and infrastructure of the healthcare system, particularly in rural underserved areas, should be intensified to help vulnerable communities.