title: Phylogenetic analyses reveal HIV-1 infections between men misclassified as heterosexual transmissions.
abstract: OBJECTIVE
  HIV-1 subtype B infections are associated with MSM in the UK. Yet, around 13% of subtype B infections are found in those reporting heterosexual contact as transmission route. Using phylogenetics, we explored possible misclassification of sexual exposure among men diagnosed with HIV in the UK.
  
  
  METHODS
  Viral gene sequences linked to patient-derived information were used to identify phylogenetic transmission chains.
  
  
  METHODS
  A total of 22,481 HIV-1 subtype B pol gene sequences sampled between 1996 and 2008 were analysed. Dated phylogenies were reconstructed and transmission clusters identified as clades of at least two sequences with a maximum genetic distance of 4.5%, a branch support of at least 95% and spanning 5 years. The characteristics of clusters containing at least one heterosexually acquired infection were analysed.
  
  
  RESULTS
  Twenty-nine percent of the linked heterosexuals clustered exclusively with MSM. These were more likely to be men than women. Estimated misclassification of homosexually acquired infections ranged between 1 and 11% of the reported male heterosexuals diagnosed with HIV. Black African heterosexual men were more often phylogenetically linked to MSM than other ethnic group, with an estimated misclassification range between 1 and 21%.
  
  
  CONCLUSIONS
  Overall, a small proportion of self-reported heterosexual men diagnosed with HIV could have been infected homosexually. However, up to one in five black African heterosexual men chose not to disclose sex with men at HIV diagnosis and preferred to be identified as heterosexual. Phylogenetic analyses can enhance surveillance-based risk information and inform national programmes for monitoring and preventing HIV infections.
authors.affiliation: aDepartment of Infection, University College London bHIV and STI Department, Public Health England, London cSchool of Biological Sciences, University of Edinburgh, Edinburgh dInstitute of Biodiversity, University of Glasgow, Glasgow eMedical Research Council Clinical Trial Unit fHIV and Sexual Health Clinic, Chelsea and Westminster Hospital, London, UK.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Hué
authors.forename: Alison E
authors.initials: AE
authors.lastname: Brown
authors.forename: Manon
authors.initials: M
authors.lastname: Ragonnet-Cronin
authors.forename: Samantha J
authors.initials: SJ
authors.lastname: Lycett
authors.forename: David T
authors.initials: DT
authors.lastname: Dunn
authors.forename: Esther
authors.initials: E
authors.lastname: Fearnhill
authors.forename: David I
authors.initials: DI
authors.lastname: Dolling
authors.forename: Anton
authors.initials: A
authors.lastname: Pozniak
authors.forename: Deenan
authors.initials: D
authors.lastname: Pillay
authors.forename: Valerie C
authors.initials: VC
authors.lastname: Delpech
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Leigh Brown
mesh_terms: D000293:Adolescent; D000328:Adult; D016000:Cluster Analysis; D005260:Female; D005838:Genotype; D015658:HIV Infections / Q000453:epidemiology / Q000635:transmission* / Q000821:virology*; D015497:HIV-1 / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D006801:Humans; D008297:Male; D008875:Middle Aged; D017720:Molecular Epidemiology; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D012725:Sexual Behavior; D006113:United Kingdom / Q000453:epidemiology; D055815:Young Adult; D054302:pol Gene Products, Human Immunodeficiency Virus / Q000235:genetics
chemical_list: D054302:pol Gene Products, Human Immunodeficiency Virus