Background: The COVID-19 pandemic has magnified existing health disparities for marginalized populations in the United States (U.S.), particularly among Black Americans. Social determinants of health are powerful drivers of health outcomes that could influence COVID-19 racial disparities.

Methods: We collected data from publicly available databases on COVID-19 death rates through October 28, 2020, clinical covariates, and social determinants of health indicators at the U.S. county level. We utilized negative binomial regression to assess the association between social determinants of health and COVID-19 mortality focusing on racial disparities in mortality.

Results: Counties with higher death rates had a higher proportion of Black residents and greater levels of adverse social determinants of health. A one percentage point increase in percent Black residents, percent uninsured adults, percent low birthweight, percent adults without high school diploma, incarceration rate, and percent households without internet in a county increased COVID-19 death rates by 0.9% (95% CI 0.5%-1.3%), 1.9% (95% CI 1.1%-2.7%), 7.6% (95% CI 4.4%-11.0%), 3.5% (95% CI 2.5%-4.5%), 5.4% (95% CI 1.3%-9.7%), and 3.4% (95% CI 2.5%-4.2%), respectively. Counties in the lowest quintile of a measure of economic privilege had an increased COVID-19 death rates of 67.5% (95% CI 35.9%-106.6%). Multivariate regression and subgroup analyses suggested that adverse social determinants of health may partially explain racial disparities in COVID-19 mortality.

Conclusions: This study demonstrates that social determinants of health contribute to COVID-19 mortality for Black Americans at the county level, highlighting the need for public health policies that address racial disparities in health outcomes.