Origin and evolution of subtype B variants in the former Soviet Union countries

Contrary to the global trend, between 2010 and 2020, an increase of 43% new HIV infections was recorded in Eastern Europe and Central Asia. Analyses of phylogenetic relationship, and routes and modes of transmission of the HIV-1 subtype B across the former Soviet Union (FSU) region are currently lacking. The objective of this analysis was to investigate the origin and transmission routes of HIV subtype B in FSU countries. We performed phylogenetic and phylodynamic analyses using 21,007 publicly available subtype B sequences from Europe and Asia, including thirteen FSU countries. Our study suggests that BFSU strain evolved more recently in FSU countries (Russia, Kyrgyzstan, Uzbekistan, Tajikistan, Belarus, Ukraine, Lithuania, Latvia, Georgia, Armenia, Azerbaijan) compared to the Western B variant in Western Europe (Austria, Belgium, Germany, Luxembourg, Netherlands, Switzerland). The primary high-risk group responsible for the transmission of subtype B was found to be MSM/homosexual. Intermixing of phylogenetic clusters among high-risk groups and bridging with the general population indicated that the HIV epidemic is no longer confined to distinct key populations - emphasizing an urgent need to improve the HIV harm-reduction efforts among high risk as well as general populations.