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

Abstract

PurposeThe 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. MethodsWe 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. ResultsOf 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 <13 years at diagnosis (40.9%), Asians (32.1%), persons born outside the United States (22.6%), and persons with infection attributable to heterosexual contact (12.0%–15.0%). Prevalence of non-B infections increased from 5.9% in 2006 to 8.5% in 2013. ConclusionsSubtype B continues to predominate in the United States. However, the percentage of non-B infections has grown in recent years, and numerous demographic subgroups have much higher prevalence. Subgroups and areas with high prevalence of non-B infections might represent sub-epidemics meriting further investigation.