ABSTRACT
Few pandemic control measures have been as contentious as border-linked disease control interventions. Mathematically complex, but naïve, models that treat communicable disease spread as a process akin to diffusion fail to capture the important impact of borders, while models that focus solely on “introduction” fail to consider gaps between countries with respect to control of diseases once introduced. I propose that so-called gravity models, which treat the “pull” that different jurisdictions exert on each other across boundaries in a manner akin to gravitational forces acting between planets, provide actionable insights into potential impacts of border control, including the nonutility of border controls for long-term prevention of disease introduction, the influence of highly connected 3rd countries in disease emergence, and the dominant importance of local “soil” (conditions permitting epidemic growth) as opposed to “seed” (pathogen introduction) in determining the impact of international movement of a novel disease.
