Although increasing vaccine uptake is a key strategy to minimize COVID-19 deaths, evidence of the role of vaccination rates in attenuating the socioeconomic disparity in COVID-19 deaths is limited. We thus aimed to quantify the extent to which vaccination rates contribute to the association between US county-level poverty rates and COVID-19 mortality rates.
This nationwide study analyzed data on 3,142 US counties. We conducted mediation analyses to calculate the proportions eliminated (PE) of the association between poverty rate and COVID-19 deaths per 100,000 population by setting the COVID-19 vaccination rate (the proportion of fully vaccinated individuals as of December 31, 2021) to different observed values.
Adjusted for county-level characteristics, we estimate an additional 25.3 COVID-19 deaths per 100,000 population for each 10% increase in a county’s poverty rate. When we set the vaccination rate at its maximum, 90 percentile, and 75 percentile of the observed values, the PE was estimated to be 81% (P < 0.001), 37% (P < 0.001), and 21% (P < 0.001), respectively.
Higher county-level poverty rates and lower vaccination rates were associated with greater COVID-19 mortality rates in the US. Aggressive interventions to increase vaccine uptake could substantially reduce the social disparity in COVID-19 mortality.

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