Genomic surveillance uncovers regional variation in HCV transmission networks among people who use drugs in rural U.S. communities.

Hepatitis C virus (HCV) remains a significant public health concern in the United States particularly in rural communities where the opioid epidemic has accelerated transmission among people who use drugs (PWUD)/ Despite, this growing burden the genetic features and transmission patterns of HCV in these settings are poorly understood. This study analyzed 692 HCV antibody-positive specimens collected from rural communities in ten U.S. states. Using amplicon-based deep sequencing and the Global Hepatitis Outbreak and Surveillance Technology (GHOST) platform, transmission networks were reconstructed. Among sequenced individuals, 29.5% were linked within clusters. The structure of these clusters varied by region-from sparse networks in Ohio to dense, interconnected clusters in New England. Phylogenetic analysis revealed that some transmission networks persisted for over a decade, highlighting long-term, sustained transmission. Nearly half of all clusters involved individuals connected through social recruitment, suggesting peer-referral strategies can effectively identify transmission chains. Younger age was independently associated with clustering, while recruitment by an intimate partner showed a weaker link. These findings emphasize the importance of ongoing genomic surveillance and social network-informed strategies to detect emerging HCV clusters and guide targeted public health interventions in underserved rural communities.