Integrated Diagnosis of Hepatitis B, C, and D Viruses and HIV in Populations Evaluated for Sexually Transmitted Infections: A Narrative Review and Operational Framework.

Hepatitis B virus (HBV), hepatitis C virus (HCV), and hepatitis D virus (HDV), together with HIV and bacterial sexually transmitted infections (STIs), account for a rising toll of more than one million deaths annually and overlap within shared behavioral and social networks, yet are still diagnosed through separate, pathogen-specific pathways. This narrative review synthesizes contemporary evidence on the convergence between viral hepatitis, HIV, and high-risk STI groups-men who have sex with men, pre-exposure prophylaxis (PrEP) users, people practicing chemsex, people who inject drugs, incarcerated populations, and migrants from endemic regions-and characterizes the diagnostic technologies and linkage-to-care models available to address it. Despite effective antivirals, the diagnostic cascade remains the principal bottleneck: most people with chronic HCV are undiagnosed, and HDV-with a pooled anti-HDV seroprevalence of approximately 4.5% among HBsAg-positive individuals-is its clearest expression, as most carriers are never tested. Reflex algorithms, multiplex panels, point-of-care assays, dried blood spots, and electronic health record alerts are validated but unevenly implemented. We argue that, alongside persistent resource, political, and equity-related constraints, a substantial share of the remaining barriers is operational rather than purely technological, and propose a practical, STI-clinic-centered framework integrating reflex testing, population-specific periodicity, and explicit linkage pathways toward the WHO 2030 elimination targets.