Racial Disparities in Coronavirus Disease 2019 (COVID-19) Mortality Are Driven by Unequal Infection Risks

Abstract

Background: As of 1 November 2020, there have been >230 000 deaths and 9 million confirmed and probable cases attributable to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the United States. However, this overwhelming toll has not been distributed equally, with geographic, race/ethnic, age, and socioeconomic disparities in exposure and mortality defining features of the US coronavirus disease 2019 (COVID-19) epidemic.

Methods: We used individual-level COVID-19 incidence and mortality data from the state of Michigan to estimate age-specific incidence and mortality rates by race/ethnic group. Data were analyzed using hierarchical Bayesian regression models, and model results were validated using posterior predictive checks.

Results: In crude and age-standardized analyses we found rates of incidence and mortality more than twice as high than for Whites for all groups except Native Americans. Blacks experienced the greatest burden of confirmed and probable COVID-19 (age-standardized incidence, 1626/100 000 population) and mortality (age-standardized mortality rate, 244/100 000). These rates reflect large disparities, as Blacks experienced age-standardized incidence and mortality rates 5.5 (95% posterior credible interval [CrI], 5.4-5.6) and 6.7 (95% CrI, 6.4-7.1) times higher than Whites, respectively. We found that the bulk of the disparity in mortality between Blacks and Whites is driven by dramatically higher rates of COVID-19 infection across all age groups, particularly among older adults, rather than age-specific variation in case-fatality rates.

Conclusions: This work suggests that well-documented racial disparities in COVID-19 mortality in hard-hit settings, such as Michigan, are driven primarily by variation in household, community, and workplace exposure rather than case-fatality rates.

Keywords: COVID-19; SARS-CoV-2; disparities; social epidemiology.

Figure 1.

Incidence rate estimates (points) and 95% CrI (vertical lines) of COVID-19 infection per 100 000 population by 10-year age groups, stratified by race/ethnic group. Dashed lines indicate the crude rate for each group. Abbreviations: COVID-19, coronavirus disease 2019; CrI, posterior credible interval.

Figure 2.

COVID-19 case-fatality rate estimates (points) and 95% CrI (vertical lines) by 10-year age groups, stratified by race/ethnic group. Dashed lines indicate the crude rate for each group. Abbreviations: COVID-19, coronavirus disease 2019; CrI, posterior credible interval.

Figure 3.

Disparities (as measured by rate ratios [points]) and 95% CrI (vertical lines) of COVID-19 incidence (left-hand column) and case-fatality rate (right-hand column) by age and race/ethnic group compared with White individuals. Dashed lines indicate the ratio of the crude overall rate for each group; the solid gray line is a guide for assessing the strength of association, representing a rate ratio of 1.0 (no association). Abbreviations: COVID-19, coronavirus disease 2019; CrI, posterior credible interval.