by Okan Gurbuz
Restricting travel has proven vital to stemming the tide of the COVID-19 pandemic, especially early on. Less human contact in tight spaces means less exposure to the virus—that’s a given. But reduced contact also means reduced commerce, at least for businesses depending on in-person customers.
When you add international travel into the mix, the health impact of relaxing restrictions on mobility becomes even more complex. Now that the COVID-19 delta variant is running rampant, states, cities and towns are trending toward pre-pandemic levels of activity. The question is how we do we normalize mobility for folks, both domestically and internationally, especially with the more communicable from of COVID-19 currently running rampant?
In several research projects, I and my research team at the Texas A&M Transportation Institute’s (TTI’s) Center for International Intelligent Transportation Research (CIITR) have studied the relationship between mobility and COVID-19, specifically in the El Paso/Ciudad Juárez, Mexico, region. We looked at cross-border travel levels during and after the pandemic at its most virulent. We also studied daily infection and vaccination rates on both sides of the border, as well as the number of daily trips made each month from January 2019 (pre-pandemic) through March 2021 (throughout and after quarantine) to quantify how movement restrictions impacted travel volume.
For example, in January 2019, there were nearly 80,000 crossings daily on average into El Paso County from Ciudad Juárez. By March 2020 — one month after border travel restrictions were introduced — there were 20,000. That number has trended upward since, with March 2021 seeing just over 40,000 crossings. We also looked at travel within El Paso County, which dropped 85 percent from nearly 700,000 daily trips (January 2020) to just over 100,000 (April 2020). Every one of these trips, international or otherwise, carries with it the potential to spread the virus.
Using this data, we were able to generate an epidemiological model to simulate the relationship between COVID-19 infections and travel, both from Ciudad Juárez into El Paso County and within the county itself. We determined that the variables most significantly impacting El Paso infection rates — and, subsequently, hospitalizations and deaths — involved commuting and mobility, whether within El Paso County or cross-border.
In early August 2021, we updated our research to account for the more communicable COVID-19 delta variant. That also brought up-to-date our predictions for the number of cases and fatalities under different scenarios looking at total cases and deaths as the vaccination rate in El Paso scales up.
Our findings confirm that—as long as a significant share of the population remains unvaccinated—increasing commutes within El Paso County or from Ciudad Juárez into El Paso will result in increased infections, hospitalizations and deaths. We further project that increasing the fully vaccinated population in El Paso to 85 or 90 percent will save 32 or 58 lives, respectively, over the next year.
When’s the right time to relax (or remove altogether) travel restrictions? That’s a question for elected officials. The point is, it doesn’t matter whether it’s international or domestic travel. Mobility of any kind facilitates the spread of infectious diseases, including COVID-19, whatever its variant. Increased vaccinations—together with a measured approach to reopening travel—will save lives.
Okan Gurbuz is an assistant research scientist in TTI’s El Paso Research and Implementation Office.