As a result of the high mutation, recombination and replication rates of HIV-1,
its recombinant forms are becoming increasingly complex.1 The coinfection and recombination of different HIV-1 subtypes create many opportunities for the emergence of new recombinant forms. To date, more than 150 circulating recombinant forms (CRFs) and numerous unique recombinant forms (URFs) have been identified by the analysis of near-full-length genomes (NFLGs) globally. Furthermore, a new CRF will emerge if more than three URFs with the same recombinant structure are found in different areas with no epidemiological linkage.
In contrast to global HIV-1 diversity, Chinese HIV-1 recombinant strains are more frequently detected.1
In Hebei, CRF01_AE, CRF07_BC and subtype B were the dominant HIV-1 subtypes, similar to the dominant subtypes across the whole of China. However, recently, many other subtypes such as CRFs_0107, URFs_0107, CRFs_01B and URFs_01B have been continually identified in Hebei among the sexually-active population, especially among men who have sex with men (MSM). For example, CRF80_0107, CRF103_01B and CRF123_0107 were detected circulating in the MSM population in 2019, 2020 and 2022, respectively.2-4
Baoding is the second largest city with HIV/AIDS cases in Hebei Province, and MSM are the most affected population.5 Over the past three years, two new CRFs (CRF103_01B and CRF123_0107) and many URFs have been reported in Baoding. However, no novel second-generation recombinant CRFs were confirmed among the minor subtypes. In this study, we identified a new HIV-1 second-generation circulating recombinant CRF159_01103 composed of CRF103_01B and CRF01_AE among MSM in Baoding, Hebei Province, and analyzed its evolutionary history.