Adaptive urban and architectural strategies for infectious disease resilience: The exceptional convergence of the 2025 Jubilee and Papal events in Rome, Italy

Mass gathering events are increasingly recognised as a critical issue in public health, owing to their potential to amplify the transmission of infectious diseases and to strain the adaptive capacity of urban systems. The convergence of large populations within densely inhabited metropolitan environments poses intricate challenges for infection prevention, environmental safety, and mobility management, particularly in historic cities where spatial and infrastructural flexibility is inherently constrained. This study examines an exceptional and unforeseen scenario that unfolded in Rome, Italy, during the 2025 Jubilee, one of the most significant celebrations of the Catholic Church. During this period, an unpredictable overlap of several major religious events, including the Papal Requiem, the Conclave, and the Papal Election, coincided with the Catholic Easter. This conjunction, superimposed upon the regular seasonal influx of international tourists to one of the world’s foremost heritage destinations, produced a sudden and large-scale mass gathering event that exceeded conventional preparedness expectations. The resulting spatial and social convergence exposed the vulnerabilities of even advanced urban systems to compounded health and logistical pressures, particularly those related to the airborne and contact-based transmission of infectious diseases. Beyond the contextual analysis, the paper explores how resilient urban and architectural strategies, conceived in advance and embedded within comprehensive preparedness frameworks, could be activated on demand to mitigate the impact of such complex events. These include adaptive modular infrastructures, temporary spatial reconfigurations, and the integration of digital technologies for real-time environmental and epidemiological monitoring. Collectively, these approaches define a forward-looking paradigm for enhancing the anticipatory capacity of metropolitan environments, ensuring that cities remain both functional and health-secure under the exceptional pressures generated by unforeseen mass gatherings. • The unforeseen overlap of the 2025 Jubilee with Catholic Easter, a Papal Requiem, Conclave, and Papal Election created an exceptional convergence of mass gatherings, amplifying public health risks in Rome’s dense historic core. • Urban morphology and crowd dynamics emerged as critical, yet underrecognized, determinants of disease transmission, highlighting the need for geospatial risk stratification. • A multidisciplinary framework combining adaptive architectural interventions (e.g., modular structures, one-way circulation) with real-time digital monitoring and predictive analytics was identified as a rapidly deployable, cost-efficient strategy. • This approach offers a scalable model for safeguarding health during large-scale events in heritage cities with infrastructural and environmental constraints.