Distribution and time trends of HIV-1 variants in Poland : characteristics of non-B clades and recombinant viruses

The spread of HIV-1 subtypes varies considerably both worldwide and within Europe, with non-B variants commonly found across various exposure groups. This study aimed to analyse the distribution and temporal trends in HIV-1 subtype variability across Poland. For analysis of the subtype distribution, 1219 partial pol sequences obtained from patients followed up in 9 of 17 Polish HIV treatment centres were used. Subtyping was inferred using the maximum likelihood method; recombination was assessed using the bootscanning and jumping profile hidden Markov model methods. Subtype B dominated in the studied group (n=1059, 86.9%); in 160 (13.1%) sequences, non-B variants were present [A1 (n=63, 5.2%), D (n=43, 3.5%), C (n=22, 1.8%), and F1 (n=2, 0.2%)]. In 25 (2.1%) cases circulating recombinant forms (CRFs) were found. Five A1 variants (0.4%) were unique AB recombinant forms (URF) not previously identified in Poland. Non-B clades were notably more common among females (n=73, 45.6%, p