COVID-19 Pandemic
Impact of Border Proximity on COVID-19 Incidence and Mortality along the U.S.-Mexico Border Berenice Arguello* Berenice Arguello Arguello Arguello Arguello Arguello Arguello University of California, San Francisco
Viral epidemics expose the vulnerabilities of interconnected healthcare systems, especially in regions where borders do not prevent the spread of disease. “Binational health” refers to the health challenges of the U.S.–Mexico border region that stem from social ties, cultural connections, travel, economics, migration, and consumption. In this study we sought to quantify COVID-19 incidence and mortality in U.S. border state counties, compare these indicators between border and non-border counties, and visualize disparities through geographic mapping.
This retrospective cohort study analyzed publicly available, deidentified data from the Centers for Disease Control and Prevention and the U.S. Census Bureau between January 2020 and May 2023 to calculate incidence and mortality for all counties within U.S. border states. Counties situated within 100 km of the U.S.-Mexico border were classified as border counties. Spatial mapping using geographic information system software was conducted to visualize trends and disparities.
Annual incidence and mortality showed higher COVID-19 burden in US–Mexico border counties. In 2020, mean case incidence was 170 vs 120 per 100,000 person-weeks, rising by 2022 to 560 vs 450. Mortality was also higher in border counties (2020: 2.8 vs 2.5; 2022: 8.9 vs 7.5 per 100,000). Relative risk analyses also demonstrated higher weekly case risk in 2020 (RR 1.2, CI 1.15–1.26, p<0.0001) and death risk (RR 1.44, CI 1.15–1.80, p<0.001) in border counties. Cumulative RR of death ranged 1.44–0.98, significant only in 2020–2021.
Proximity to the U.S.–Mexico border is associated with measurable differences in COVID-19 incidence and mortality. Most apparent was in the year 2020, when new cases and deaths per week RR was highest. The risk of new deaths in border counties reduced by 2022, but incidence of new COVID-19 cases remained significantly higher. Identifying these disparities bring attention to the need for intrastate/interstate preparedness and advocate for equitable resource allocation during future emergencies.
