Hospital-Based Models of Immunization for High-Risk Subjects in Lombardy (Italy): A Region-Wide Assessment of Implementation and Progress

Background: In the context of a multi-stakeholder program promoted by Regione Lombardia in collaboration with Fondazione The Bridge and the University of Pavia, the present study investigates the organization and availability of hospital-based vaccination services for high-risk patients. Framing hospitals as strategic hubs for vaccination delivery, the study aimed to map service availability, operational settings and dedicated pathways across the region. Methods: A structured questionnaire was administered in 2025 to 40 healthcare organizations, encompassing 114 hospital facilities, including Local Health and Social Care Authorities (ASSTs) and both public and private Scientific Institutes for Research, Hospitalization and Healthcare (IRCCSs). Descriptive and inferential statistical analyses were performed, and findings were compared with those from the 2023 and 2024 editions of the same survey, developed within the “Vaccination—an opportunity for high-risk patients” project, using Pearson’s chi-square test. Results: In 2025, 99 facilities (86.8% of respondents) reported providing vaccination services for at-risk individuals. Dedicated vaccination pathways were generally available in more than 50% of facilities for nearly two-thirds of the risk categories considered. Vaccination services for diabetic patients were available in 70.7% of facilities. Among healthcare workers, influenza (93%) and SARS-CoV-2 (89.5%) vaccines were the most frequently offered, with rates approximately ten percentage points higher than those of other vaccines. Conclusions: Overall, these findings indicate a regional model progressively consolidating hospital-based vaccination for high-risk groups, with a consistent upward trend in service availability from 2023 to 2025.