title: Recent HIV-1 infection contributes to the viral diffusion over the French territory with a recent increasing frequency.
abstract: OBJECTIVE
  To analyse the contribution of primary human immunodeficiency virus type 1 (HIV-1) infection (PHI) to the French viral epidemic.
  
  
  METHODS
  HIV-1 pol sequences included 987 PHI from the French ANRS PRIMO cohort between 1999 and 2010 and were analysed using a population-based phylogenetic approach. Clinical features, risk factors, sexual behaviour and drug resistance for clustered and nonclustered transmission events were ascertained.
  
  
  RESULTS
  Viruses from 125 (12.7%) of PHI cosegregated into 56 transmission chains, with increasing frequency during the last years (10.2% before 2006 versus 15.2% of clusters in 2006-2010, p = 0.02). The mean number of patients per cluster was 2.44. Compared to unique PHI, clusters involved more often men, infected through homosexual intercourse, of young age, with a high number of casual sexual partnerships and frequent previous HIV serological tests. Resistant strains were found in 16.0% and 11.1% of clusters and unique PHI, respectively (p = 0.11). Overall, 34% (n = 9) clusters included patients followed in French regions far apart, involving 13 clusters with at least one Parisian patient.
  
  
  CONCLUSIONS
  PHIs are a significant source of onward transmission, especially in the MSM population. Recently infected people contribute to the spread of the viral epidemic throughout the French territory. Survey of transmitted drug resistance and behavioural characteristics of patients involved into clustered PHI may help to guide prevention and treatment interventions.
authors.affiliation: Université Paris-Descartes, Equipe d'accueil 3620, Sorbonne Paris Cité, Paris, France. pierre.frange@nck.aphp.fr
authors.forename: Pierre
authors.initials: P
authors.lastname: Frange
authors.forename: Laurence
authors.initials: L
authors.lastname: Meyer
authors.forename: Christiane
authors.initials: C
authors.lastname: Deveau
authors.forename: Laurent
authors.initials: L
authors.lastname: Tran
authors.forename: Cecile
authors.initials: C
authors.lastname: Goujard
authors.forename: Jade
authors.initials: J
authors.lastname: Ghosn
authors.forename: Pierre-Marie
authors.initials: PM
authors.lastname: Girard
authors.forename: Philippe
authors.initials: P
authors.lastname: Morlat
authors.forename: Christine
authors.initials: C
authors.lastname: Rouzioux
authors.forename: Marie-Laure
authors.initials: ML
authors.lastname: Chaix
mesh_terms: D004351:Drug Resistance; D005260:Female; D005602:France / Q000453:epidemiology; D015658:HIV Infections / Q000453:epidemiology* / Q000635:transmission; D015497:HIV-1 / Q000302:isolation & purification*; D006801:Humans; D015994:Incidence; D008297:Male; D012307:Risk Factors; D012725:Sexual Behavior; D054302:pol Gene Products, Human Immunodeficiency Virus / Q000032:analysis
chemical_list: D054302:pol Gene Products, Human Immunodeficiency Virus