When mobility matters: How inter-regional travel shapes the effectiveness of local epidemic interventions

In today’s interconnected world, increased inter-regional mobility accelerates the spread of infectious disease, challenging the design of effective intervention strategies. Non-pharmaceutical interventions (NPIs), including travel restrictions and local measures such as school closure and social distancing, are key to early containment, especially for the newly emerged infectious disease. While many studies evaluate these NPIs independently, how will the travel patterns shape transmission and alter the effectiveness of local interventions remains a critical gap. We develop an age-structured metapopulation model with four age-specific contact matrices to assess these effects. Our findings show that high inter-regional mobility increases the final and peak symptomatic infections by 13.6% and over 10%, respectively. Crucially, under high mobility, ignoring inter-regional travel leads to over 40% overestimation of local NPIs’ effectiveness. Incorporating travel restrictions significantly boosts the impact of local measures, improving control outcomes. These results highlight the importance of considering inter-regional mobility when designing and evaluating local NPIs to ensure accurate assessment and effective epidemic response.