Spatial Inequities in COVID-19 Testing, Positivity, Incidence and Mortality in 3 US Cities: a Longitudinal Ecological Study

Background: Preliminary evidence has shown inequities in COVID-19 related cases and deaths in the US. Objective: We explored the emergence of spatial inequities in COVID-19 testing, positivity, incidence, and mortality in New York City, Philadelphia, and Chicago during the first six months of the pandemic. Design: Ecological, observational study at the zip code tabulation area (ZCTA) level from March to August 2020. Setting: Chicago, New York City and Philadelphia. Participants: All populated ZCTAs in the three cities. Measures: Outcomes were ZCTA-level COVID-19 testing, positivity, incidence, monthly from pandemic onset through the end of August, and ZCTA-level COVID-19 mortality cumulatively through the end of August. Predictors were the CDC social vulnerability index and its four domains, obtained from the 2014-2018 American Community Survey. We examined spatial clusters of COVID-19 outcomes using local Moran9s I and estimated associations using negative binomial models. Results: We found spatial clusters of high and low positivity, incidence and mortality, co-located with clusters of low and high social vulnerability. We also found evidence for the existence of spatial inequities in testing, positivity, incidence and mortality for the three cities. Specifically, neighborhoods with higher social vulnerability had lower testing rates, higher positivity ratios, incidence rates and mortality rates. Inequities in testing and incidence changed over time in the three cities, and inequities in positivity stayed consistent over time. Limitations: ZCTAs are imperfect and heterogeneous geographical units of analysis. We rely on surveillance data, which may be incomplete. Conclusion: We found spatial inequities in COVID-19 testing, positivity, incidence, and mortality in three large cities of the US.