Resistance in non-B HIV subtypes

It is estimated that one quarter of HIV-infected people in the United Kingdom have contracted a non-B subtype. Such infections are found almost exclusively among people who have contracted HIV through heterosexual sex.

A British study of over 600 people born in the United Kingdom or Europe found that 14% of the men and 35% of the women were infected with non-B subtypes. 1 Many clinics in metropolitan cities across Europe now routinely report 25 to 40% of their patient profile as having non-B clade virus, including London-based hospitals.

Due to the preponderance of the B subtype in western countries, resistance research has focused on the evolution and mutations associated with the B subtype. Little is known about how drug resistance may evolve differently in people infected with non-B subtypes, although this is a growing area of interest. Just over 90% of all HIV-1 infections are non-subtype B variants.2

There is increasing recognition of the impact subtype has on pathways to resistance during HIV treatment. There is also recognition of the need for further research in non-B subtypes to inform the treatment decisions of people with non-B subtypes and the analysis of their resistance assays.

The results of a genotypic interpretation algorithm will vary by subtype. The extent to which specific subtype-dependent mutations influence response to therapy is not fully understood.3


  1. Parry JV et al. National surveillance of HIV-1 subtypes for England and Wales: design, methods, and initial findings. J Acquir Immune Defic Syndr 26: 381-388, 2001
  2. Martinez-Cajas J et al. Differences in resistance mutations among HIV-1 non-subtype B infections: a systematic review of evidence (1996-2008). J Int AIDS Soc 12(1): 11, 2009
  3. Snoeck J et al. Discordances between interpretation algorithms for genotypic resistance to protease and reverse transcriptase inhibitors of human immunodeficiency virus are subtype dependent. Antimicrob Agents Chemother 50(2): 694-701., 2006
Community Consensus Statement on Access to HIV Treatment and its Use for Prevention

Together, we can make it happen

We can end HIV soon if people have equal access to HIV drugs as treatment and as PrEP, and have free choice over whether to take them.

Launched today, the Community Consensus Statement is a basic set of principles aimed at making sure that happens.

The Community Consensus Statement is a joint initiative of AVAC, EATG, MSMGF, GNP+, HIV i-Base, the International HIV/AIDS Alliance, ITPC and NAM/aidsmap

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