Tracking HIV-1 Genetic Epidemiological Characteristics Among Recent Infections in Yunnan, China.

Yunnan Province is one of the provinces in China severely affected by HIV-1. To track the evolution and epidemiological characteristics of HIV-1 genetics in Yunnan Province, this study conducted a retrospective molecular epidemiological study of HIV-1 in new infections in Yunnan Province. From the newly reported HIV-infected individuals throughout Yunnan Province from January to March 2018, cases with CD4⁺ T lymphocytes less than 200 cells/µL were excluded for BED capture enzyme immunoassay (BED-CEIA). Samples identified as recent infections by BED-CEIA were subjected to viral gene amplification to analyze the distribution characteristics of HIV-1 genotypes and the prevalence of pretreatment resistance. Of the 1,740 samples tested by BED-CEIA, 448 were identified as newly infected, and 323 were successfully genotyped; 14 HIV-1 genotypes were identified, including 2 subtypes, 11 circulating recombinant forms (CRFs), and several unique recombinant forms (URFs), of which CRF08_BC (37. 5%, 121/323), CRF07_BC (22.6%, 73/323), URFs (18.3%, 59/323), and CRF01_AE (14.9%, 48/323) were the predominant genotypes. CRF08_BC had higher proportions in the northeastern, southeastern, central, and southwestern regions of Yunnan Province than in the northwestern region and was more common in the 40-49-year age group, married, and heterosexual contacts. CRF01_AE had significantly higher proportions in the southeastern and northwestern regions and among those with homosexual contact, whereas no significant correlations were found for CRF07_BC and URFs. The overall prevalence of pretreatment resistance was 8.5% [95% confidence interval (CI): 5.5%-12.4%], with the highest proportion of resistance to nonnucleoside reverse transcriptase inhibitors (NNRTIs; 6.0%, 95% CI: 3.5%-9.4%). This study demonstrated the genetic diversity and regional and subpopulation distribution characteristics of the recently infected HIV-1 population in Yunnan Province, and that pretreatment resistance was at a moderate level, but resistance to NNRTIs needs attention. This study provided the baseline data for a systematic study of the evolution of HIV-1 genetics in a typical endemic area.