A Two-Region SEIR COVID-19 Epidemic Model for the Island of Ireland

Abstract The island of Ireland consists of two countries, Ireland and Northern Ireland, which are separated by a land border. We develop a model for the COVID-19 epidemic which consists of two SEIR models, one for each country, coupled through border interaction terms. The model incorporates symptomatic and presymptomatic infectives, but not asymptomatic infectives, together with a simple isolation/quarantine model. The objective of the work is to explore how the two-region epidemic could evolve by examining selected regions of parameter space. In this context we examine the effect of the border status on evolution of the epidemic. We found that, even though the border interaction parameters are relatively small, the open border could significantly affect the course of the epidemic in some of the scenarios studied. We also looked for and found examples of sensitive dependence on several parameters.