Population Mobility and Socioeconomic Indicators in California, USA and Ontario, Canada during the COVID-19 Pandemic

PURPOSE: To explore the extent that socioeconomic indicators influenced mobility of populations during the COVID-19 pandemic in two jurisdictions. METHODS & MATERIALS: We used anonymized, population-aggregated mobile-device location data to estimate dynamic changes in population mobility patterns across the province of Ontario, Canada and the state of California, U.S.A. Data from the Ontario-Marginalization Index at the Census Subdivision (CSD) level, as well as the California Healthy Places Index (HPI) at the Census Tract (CT) level, were used to determine the census geographical units in the lowest and highest quantiles of socioeconomic indicators during the COVID-19 pandemic. Ontario was under three province-wide stay-at-home orders between March 17, 2020 and June 2, 2021. California was under state-wide stay-at-home orders from March 19, 2020 to January 25, 2021. Weekly data from March 15, 2020 to June 19, 2021 were analyzed for Ontario, and weekly data were analyzed from March 15, 2020 to March 20, 2021 for California. We used the percentage of time spent away from home as the indicator for mobility and analyzed differences in mobility trends between the populations grouped by material deprivation score (Ontario) and HPI scores. RESULTS: In Ontario, populations with highest material deprivation spent an average of 25.7% of time away from home, while the populations with lowest material deprivation spent an average of 22.6% of their time away from home (difference: 3.1%, p <0.001) across the entire duration of the COVID-19 pandemic. Similarly, in California, the least advantaged populations spent an average of 30.0% of time away from their home, while the most advantaged populations spent 24.3% of their time away from home (difference: 5.7%, p <0.001). CONCLUSION: Across both geographical locations, the least advantaged populations observed highest mobility compared to the most advantaged populations throughout the pandemic. This indicates that populations in communities with the least advantage in Ontario and California may have less ability or inadequate resources to comply with stay-at-home orders, leading to increased risk of COVID-19 exposure among these more mobile populations. Strategies to protect those most at risk of exposure to COVID-19 are imperative for controlling spread within communities.