Mass gatherings speed up citywide spread of infectious diseases
Hybrid epidemic simulation framework coupling equation-based and individual-based models
Computers and SocietyMultiagent Systems
Summary
Big public events like concerts or sports games bring many people close together, which can cause bursts of infections that affect an entire city. The authors created a computer model that connects how people meet at events with how they travel across a city to see how these gatherings influence the spread of disease. They found that events make outbreaks bigger and faster, and that conditions after the event also help predict when the disease spreads in different city areas. This shows that controlling disease at big gatherings can help slow down outbreaks in cities.
What this means in practice
- •For public health planners: Model how large events affect citywide disease spread to plan interventions that delay outbreaks across districts.
- •For urban transport modelers: Incorporate event-driven infection bursts into city commuting simulations to evaluate broader impacts on disease dynamics.
Authors
Jaeyoung Kwak, Michael H. Lees, Chin Chun Ooi, Wentong Cai
Abstract
Mass gathering events like concerts, sports matches, and festivals bring many people into close contact within a short period, creating localized bursts of infection that can shape epidemic outcomes across an entire city. To evaluate how these transient transmission events translate into broader urban impacts, we developed a simulation model linking event-scale contact dynamics with citywide commuting networks. Using Madrid, Spain, as a case study, we compared several types of gatherings and examined how their effects changed under different levels of disease transmissibility. We found that mass gatherings consistently amplified outbreak magnitude, accelerated progression, advanced district-level arrival times, and synchronized spatial spread. Remarkably, while the initial seed size generated at the event accounted for much of this acceleration, post-event transmission conditions provided complementary predictive signal regarding invasion timing. These findings demonstrate that mitigating transmission during mass gatherings can yield downstream public health benefits by delaying broader spatial spread. More generally, this multiscale framework offers a tool to evaluate how temporary, localized contact shifts produce longer-lasting consequences for urban populations.