Increasing HIV-1 subtype diversity in seven states, United States, 2006–2013

Abstract Purpose The aim of the analysis was to explore HIV-1 subtype diversity in the United States and understand differences in prevalence of non-B subtypes and circulating recombinant forms (CRFs) between demographic/risk groups and over time. Methods We included HIV-1 polymerase sequences reported to the National HIV Surveillance System for HIV infections diagnosed during 2006–2013 in seven states. We assigned subtype or CRF using the automated subtyping tool COMET, assessed subtype/CRF prevalence by demographic characteristics and country of birth, and determined changes in subtype/CRF by HIV diagnosis year. Results Of 32,968 sequences, 30,757 (93.3%) were subtype B. The most common non-B subtypes and CRFs were C (1.6%), CRF02_AG (1.4%), A (0.6%), CRF01_AE (0.5%), and G (0.3%). Elevated percentages of non-B infections occurred among persons aged