Abstract
People living in situations of vulnerability (PSV), such as migrants, people who use drugs, people in prison, sex workers, LGBTQIA+ individuals, face a disproportionate burden of HIV, viral hepatitis, and sexually transmitted infections (STIs), yet remain systematically underrepresented in routine surveillance. These vulnerabilities rarely occur in isolation; they overlap, intersect and unfold across institutional, community and structurally segregated settings, creating a complexity that institutional data systems are poorly equipped to capture. Fragmentation between healthcare, public health, and community-based services, combined with limited data interoperability, produces incomplete epidemiological intelligence and a surveillance blind spot where the burden is highest, constraining the ability to plan, target and evaluate equitable public health responses. This workshop explores how community-based data systems can address this complexity. CBOs, low-threshold services and settings such as prisons are not merely service delivery points: they generate detailed, real-world data on populations rarely reached by institutional systems. Yet community-generated data are seldom integrated into formal surveillance frameworks, limiting their contribution to epidemiological intelligence and evidence-based policy. The objectives are: (1) identifying key structural and operational gaps in current PSV surveillance; (2) presenting real-world experiences of community-based and intersectoral data systems across institutional, harm reduction and carceral settings; (3) discussing actionable implications for governance, data interoperability and inclusive public health decision-making. Four case studies will illustrate different approaches across population groups and national contexts. The first examines the Checkpoint model in Portugal, showing how collaboration between academia, public health research and community-led testing contributes to HIV and STI monitoring beyond clinical settings. The second presents the prison sentinel network of the EU-funded PACE project, treating prisons as strategic public health sites where overlapping vulnerabilities concentrate and demonstrating how a multi-country architecture can make people in prison visible to public health surveillance. The third focuses on HCV monitoring among people who use drugs in Italy, examining how linking harm reduction and healthcare data improves epidemiological coverage. The fourth presents evidence from the EU-funded ‘Salute Inclusiva’ project on STI surveillance in Italy, focusing on governance mapping and continuity of care between the National Health Service and CBOs. Four 10-minute presentations will be followed by a facilitated discussion, generating practical insights into how to strengthen surveillance by integrating heterogeneous data sources and inform more inclusive, equitable and effective public health responses for populations that current monitoring systems often overlook.
Key messages
• Routine surveillance systematically misses groups in situations of vulnerability; the data exist, but in fragmented community, harm reduction, and carceral systems.
• Equitable public health responses require integrating these heterogeneous data sources into formal surveillance through dedicated governance and interoperability.