In vitro and in vivo model systems for Orthoflavivirus antiviral therapeutics: current landscape and strategic considerations

ABSTRACT Orthoflaviviruses represent an escalating global health challenge, encompassing a diverse group of arthropod-borne viruses that cause substantial morbidity and mortality worldwide. A critical bottleneck in drug discovery is identifying in vitro and in vivo models that accurately recapitulate human pathophysiology while remaining practical for high-throughput screening and medicinal chemistry efforts. Despite substantial preclinical activity, the paucity of clinically advanced Orthoflavivirus (hereafter referred to as flaviviruses) antivirals underscores the need for improved discovery paradigms. Refinement of antiviral assays, informed by viral biology and guided by rigorous validation principles, will be central to identifying robust small-molecule inhibitors. The convergence of high-quality phenotypic assays, precise target-based methods, and physiologically relevant models offers a promising path forward for flavivirus drug discovery and development.