HIV-1 drug resistance and molecular transmission network analysis of newly diagnosed people living with HIV in Beijing, China: a retrospective study from 2015 to 2023.

BACKGROUND: Although the annual number of newly reported human immunodeficiency virus (HIV) infections in Beijing has shown a continuous decline since 2016, the population of people living with HIV (PLWH) has maintained a persistent upward trend. This retrospective study aimed to analyse data from newly diagnosed PLWH from 2015 to 2023 in Beijing to develop precision interventions. METHODS: All newly diagnosed PLWH were subjected to sequence splicing, quality control, information matching, and analysis for pretreatment drug resistance (PDR) and molecular transmission network. The Stanford Drug Resistance Database was used to analyse drug resistance, and Hyphy and Cytoscape software were used to construct a molecular transmission network with the gene distance threshold of 0.015. RESULTS: A total of 3,569 newly diagnosed PLWH were included in this study. A total of 42 HIV-1 subtypes were identified, with CRF01_AE being the most common subtype, followed by the CRF07_BC and B subtypes. However, for the first time, the dominant strain shifted from CRF01_AE to CRF07_BC in 2023. A total of 340 drug-resistant sequences were obtained, and the overall prevalence of PDR was 9.53% from 2015 to 2023. The most common mutations were distributed among V179, K103, M184, S68 and M46, which presented diverse distributions and combined mutation features. A total of 64 transmission clusters were identified in the network, among which CRF07_BC was dominated by large spreading clusters, whereas CRF01_AE was dominated by small- and medium-sized spreading clusters. The largest cluster for CRF07_BC expanded rapidly from 8 cases in 2015 to 161 cases in 2023. CONCLUSIONS: This study revealed the prevalence of HIV-1 drug resistance and molecular transmission network in Beijing. The change in the dominant HIV strain of participants should be emphasized. Subtype CRF07_BC is prone to forming fast-spreading clusters, and targeted interventions should be designed to prevent high-risk transmission sources and reduce new HIV infections.