Changes in HIV‑1 genetic diversity among men who have sex with men living in Russia in the period 2004–2025

Introduction. Historically, men who have sex with men (MSM) are a stigmatized community in Russia, and this fact has negatively affects HIV prevention in this vulnerable group and complicates the study of HIV‑1 genetic variants. The aim of our study was to characterize HIV‑1 variants in samples obtained in 2004–2025 from MSM living in Russia. Materials and methods. Nucleotide sequences of the HIV‑1 pol gene fragment (2253–3369 bp) from the RuHIV and GenBank databases from 562 HIV-infected MSM living in the Russian Federation were analyzed. Genotyping, phylogenetic and cluster analysis were performed and p-distance calculation among the most common HIV‑1 genetic variants was carried out. Results. Sub-subtype A6 comprised 44.84% of samples, subtype B – 35.94% of samples, and the proportion of HIV‑1 sub-subtype A6 statistically significantly increased in the period 2004–2025. An increase of the p-distance was found among sub-subtype A6 (from 0.044 to 0.054) and subtype B (from 0.05 to 0.072) viruses in 2004–2025. We obtained the evidence of both the blurring of the boundaries of the vulnerable MSM group and the ongoing circulation of subtype B among MSM in Russia. The influence of migration on the increase in the number of cases of rare and recombinant forms of HIV‑1 infections among MSM in Russia in recent years was shown. Conclusion. The importance of studying the vulnerable MSM group for epidemiological surveillance of HIV infection in Russia is shown. The contribution of migration to the genetic diversity of HIV‑1 variants circulating in the country was revealed.