Exposure density and neighborhood disparities in COVID-19 infection risk

Abstract

Although there is increasing awareness of disparities in COVID-19 infection risk among vulnerable communities, the effect of behavioral interventions at the scale of individual neighborhoods has not been fully studied. We develop a method to quantify neighborhood activity behaviors at high spatial and temporal resolutions and test whether, and to what extent, behavioral responses to social-distancing policies vary with socioeconomic and demographic characteristics. We define exposure density ([Formula: see text]) as a measure of both the localized volume of activity in a defined area and the proportion of activity occurring in distinct land-use types. Using detailed neighborhood data for New York City, we quantify neighborhood exposure density using anonymized smartphone geolocation data over a 3-mo period covering more than 12 million unique devices and rasterize granular land-use information to contextualize observed activity. Next, we analyze disparities in community social distancing by estimating variations in neighborhood activity by land-use type before and after a mandated stay-at-home order. Finally, we evaluate the effects of localized demographic, socioeconomic, and built-environment density characteristics on infection rates and deaths in order to identify disparities in health outcomes related to exposure risk. Our findings demonstrate distinct behavioral patterns across neighborhoods after the stay-at-home order and that these variations in exposure density had a direct and measurable impact on the risk of infection. Notably, we find that an additional 10% reduction in exposure density city-wide could have saved between 1,849 and 4,068 lives during the study period, predominantly in lower-income and minority communities.

Keywords: COVID-19; computational modeling; geolocation data; mobility behavior; neighborhood disparities.

Fig. 1.

Neighborhood exposure density change by 250-m × 250-m grid cell (Upper) and COVID-19 positivity rate by zip code (Lower).

Fig. 2.

Agglomerative clustering results and associated neighborhood activity change. (Upper) Activity volume by land use. (Lower) Activity proportion by land use.

Fig. 3.

Scatter plot of exposure density versus the log-transformed cumulative number of COVID-19 cases through June 4, 2020, with linear best-fit lines for significant correlations. (A) Case rate. (B) Death rate. (C) Positivity rate. (D) Deaths per case. Colors represent individual clusters.