title: Epidemiology of non-B clade forms of HIV-1 in men who have sex with men in the UK.
abstract: OBJECTIVE
  To describe the frequency and risk factors of non-B HIV-1 subtypes in men who have sex with men (MSM) in the UK.
  
  
  METHODS
  Observational study.
  
  
  METHODS
  MSM diagnosed with HIV-1 infection from 1980-2007, with HIV genotype held in the UK HIV Drug Resistance Database were identified. Protease and reverse transcriptase sequences were collected and viral clade determined using the REGA algorithm. Associations between demographic variables and subtype were analysed using logistic regression.
  
  
  RESULTS
  The prevalence of non-B HIV-1 infection amongst MSM in the UK was 5.4% (437/8058). In the UK this increased with year of diagnosis from pre1996 to 2002, and has subsequently remained relatively stable at around 7-9% after 2002, with a recent increase in 2007 to 13%. Multivariate analysis showed that acquisition of non-B HIV-1 infection was independently associated with later year of HIV diagnosis (P < 0.001), black ethnicity (P < 0.001) and non-European country of birth (P = 0.01). Age was also associated with subtype with individuals aged 25-39 years being less likely to have non-B virus than those aged less than 25 years (P = 0.01). Restricting the analysis to white men born in the UK, the association between subtype and year of diagnosis remained statistically significant (P < 0.001), as did the association with age (P < 0.001).
  
  
  CONCLUSIONS
  The number of MSM in the UK infected with non-B clade HIV-1 is increasing, suggesting that the sociodemographic boundaries between HIV-1 viral subtypes globally are diminishing. Should viral subtypes be relevant to clinical disease progression or vaccine design, the changing pattern of distribution will need to be taken into account.
authors.affiliation: Department of HIV, Guys and St Thomas' NHS Trust/ Kings College London, St Thomas' Hospital, London, UK. julie.fox@kcl.ac.uk
authors.forename: Julie
authors.initials: J
authors.lastname: Fox
authors.forename: Hannah
authors.initials: H
authors.lastname: Castro
authors.forename: Steve
authors.initials: S
authors.lastname: Kaye
authors.forename: Myra
authors.initials: M
authors.lastname: McClure
authors.forename: Jonathan N
authors.initials: JN
authors.lastname: Weber
authors.forename: Sarah
authors.initials: S
authors.lastname: Fidler
mesh_terms: D000328:Adult; D000465:Algorithms; D015658:HIV Infections / Q000453:epidemiology / Q000235:genetics* / Q000276:immunology; D015497:HIV-1 / Q000145:classification / Q000235:genetics*; D018451:Homosexuality, Male; D006801:Humans; D016015:Logistic Models; D008297:Male; D015995:Prevalence; D012367:RNA, Viral / Q000235:genetics*; D012307:Risk Factors; D006113:United Kingdom / Q000453:epidemiology
chemical_list: D012367:RNA, Viral