Sequence Notes: Identification of a Novel HIV-1 Circulating Recombinant Form (CRF200_0755) in a Southern Border...

The long-term co-circulation of various HIV-1 subtypes and circulating recombinant forms (CRFs) in China has created an environment conducive to viral recombination. This study identified a novel HIV-1 CRF resulting from the recombination of CRF07_BC and CRF55_01B in Xishuangbanna Prefecture, Yunnan Province. Nearly full-length HIV-1 genome sequences were obtained from three individuals with no epidemiological link, including two men who have sex with men and one individual with heterosexual contact. These individuals were reported in 2023. These sequences form a monophyletic clade that is distinct from all known subtypes and CRFs. Recombination and phylogenetic analyses revealed that this recombinant strain exhibited a consistent mosaic genomic structure, with the CRF55_01B backbone incorporating two CRF07_BC segments. Bayesian phylogenetic analyses indicated that this recombinant form originated around 2019. In accordance with standard nomenclature, it has been designated CRF200_0755. In addition, this recombinant strain carries the V179E resistance mutation from CRF55_01B. The discovery of this novel CRF highlights the ongoing evolution of HIV-1 amid the co-circulation of prevalent strains and population mobility. It also emphasizes the importance of continuous molecular surveillance in guiding public health strategies, given the potential presence of preexisting resistance mutations.