Identification of Multiple Unique HIV-1 Recombinant Forms in Newly Reported HIV-1 Infected Individuals - Anhui Province, China, 2023.

Introduction: The genetic diversity of human immunodeficiency virus-1 (HIV-1) in China is characterized by multiple subtypes, circulating recombinant forms (CRFs) and unique recombinant forms (URFs) across the country. Through timely molecular surveillance, over 65 distinct CRFs have been identified in China to date. In this study, we identified five novel URFs among newly reported HIV-1 infected individuals in Anhui Province, China. Methods: Near-full length HIV genome sequences were obtained using two-half molecule amplification methods from five samples containing potential URFs. The sequences were subsequently subjected to phylogenetic and recombination analyses. Results: Phylogenetic and recombination analyses of the five near-full length genome sequences confirmed their classification as novel URFs. Among these, three sequences were recombinants of CRF01_AE and CRF07_BC, one sequence was a recombinant of CRF01_AE, CRF07_BC and B, and one sequence resulted from CRF07_BC and CRF08_BC recombination. Conclusions: The identification of URFs in newly infected individuals indicates ongoing transmission of multiple HIV-1 clades in Anhui Province, with superinfection occurring at notable frequencies. These findings emphasize the importance of enhancing long-term surveillance of circulating HIV-1 clades using near-full length sequence analysis in Anhui, China.