The incidence rate of Legionnaires’ disease (LDIR) has increased in many countries over the last decade. However, the combined contribution of demogr

In 2025, Rome hosted the Catholic Jubilee, recording over 33 million cumulative pilgrim attendances while simultaneously facing the death of Pope Francis, the election of Pope Leo XIV, and a regional West Nile Virus (WNV) outbreak. This commentary describes the Lazio Region’s preparedness strategy, based on adapting an existing Hub-and-Spoke infectious diseases network integrating surveillance with Regional Service for Epidemiology, Surveillance and Control of Infectious Diseases (SERESMI) laboratory support, telemedicine, and clinical management. Preparatory measures included an additional Hub, updated syndromic pathways, multidisciplinary coordination, and enhanced surveillance. Emergency department visits increased by 14.8%, while the proportion of infectious syndromes remained stable. This experience highlights the potential value of strengthening existing healthcare networks for mass gathering preparedness.