Prevalence and Response to Antiretroviral Therapy of Non-B Subtypes of HIV in Antiretroviral-Naive Individuals in British Columbia

Abstract
In North America, the B subtype of the major group (M) of HIV-1 predominates. Phylogenetic analysis of HIV reverse transcriptase and protease sequences isolated from 479 therapy-naive patients, first seeking treatment in British Columbia between June 1997 and August 1998, revealed a prevalence of 4.4% non-B virus. A range of different subtypes was identified, including one subtype A, 11 C, two D, five CRF01_AE, and one sample that could not be reliably subtyped. Baseline CD4 counts were significantly lower in individuals harbouring the non-B subtypes ( P=0.02), but baseline viral loads were similar ( P=0.80). In this study, individuals infected with non-B variants did not have a significantly different virological response to therapy after up to 18 months.