Characterization of the HIV-1 molecular network in a middle-aged population aged 50 years and older in a City in Southern Sichuan, China

This study aimed to investigate the characteristics of the HIV-1 molecular network among newly diagnosed HIV-infected patients in southern Sichuan City. Plasma samples will be collected from eligible study subjects (n = 1249) during a cross-sectional survey conducted between 2016 and 2020. The HIV-1 polymerase (pol) gene sequences obtained from the collected samples will be used to perform phylogenetic analysis and characterize the genetic subtypes' molecular transmission networks. HIV-1 pol region sequences were successfully amplified in 898 cases, and seven genotypes were obtained, with CRF01_AE (331, 36.86%) and CRF07_BC (368, 40.98%) subtypes as the predominant prevalent strains in the region. 601 sequences entered the molecular transmission network. There were 302 highly connected individuals. Further multivariate analysis showed that the older the age (60-69 years, OR = 1.595, 95% CI: 1.026-2.479; ≥70 years, OR = 2.189, 95% CI: 1.295-3.699), RX and GJ counties (OR = 4.654, 95% CI: 2.776-7.803; OR = 6.847, 95% CI: 3.464-13.533) and CRF08_BC subtype (OR = 2.031, 95% CI: 1.225-3.367) were both more likely to be highly connected individuals. To effectively combat this local HIV-1 epidemic, HIV prevention and intervention programs should target older adults at least 60 years of age and registered residents in districts and counties within RX and GJ.