title: Sexual Activity Without Condoms and Risk of HIV Transmission in Serodifferent Couples When the HIV-Positive Partner Is Using Suppressive Antiretroviral Therapy.
abstract: OBJECTIVE
  A key factor in assessing the effectiveness and cost-effectiveness of antiretroviral therapy (ART) as a prevention strategy is the absolute risk of HIV transmission through condomless sex with suppressed HIV-1 RNA viral load for both anal and vaginal sex.
  
  
  OBJECTIVE
  To evaluate the rate of within-couple HIV transmission (heterosexual and men who have sex with men [MSM]) during periods of sex without condoms and when the HIV-positive partner had HIV-1 RNA load less than 200 copies/mL.
  
  
  METHODS
  The prospective, observational PARTNER (Partners of People on ART-A New Evaluation of the Risks) study was conducted at 75 clinical sites in 14 European countries and enrolled 1166 HIV serodifferent couples (HIV-positive partner taking suppressive ART) who reported condomless sex (September 2010 to May 2014). Eligibility criteria for inclusion of couple-years of follow-up were condomless sex and HIV-1 RNA load less than 200 copies/mL. Anonymized phylogenetic analysis compared couples' HIV-1 polymerase and envelope sequences if an HIV-negative partner became infected to determine phylogenetically linked transmissions.
  
  
  METHODS
  Condomless sexual activity with an HIV-positive partner taking virally suppressive ART.
  
  
  METHODS
  Risk of within-couple HIV transmission to the HIV-negative partner.
  
  
  RESULTS
  Among 1166 enrolled couples, 888 (mean age, 42 years [IQR, 35-48]; 548 heterosexual [61.7%] and 340 MSM [38.3%]) provided 1238 eligible couple-years of follow-up (median follow-up, 1.3 years [IQR, 0.8-2.0]). At baseline, couples reported condomless sex for a median of 2 years (IQR, 0.5-6.3). Condomless sex with other partners was reported by 108 HIV-negative MSM (33%) and 21 heterosexuals (4%). During follow-up, couples reported condomless sex a median of 37 times per year (IQR, 15-71), with MSM couples reporting approximately 22,000 condomless sex acts and heterosexuals approximately 36,000. Although 11 HIV-negative partners became HIV-positive (10 MSM; 1 heterosexual; 8 reported condomless sex with other partners), no phylogenetically linked transmissions occurred over eligible couple-years of follow-up, giving a rate of within-couple HIV transmission of zero, with an upper 95% confidence limit of 0.30/100 couple-years of follow-up. The upper 95% confidence limit for condomless anal sex was 0.71 per 100 couple-years of follow-up.
  
  
  CONCLUSIONS
  Among serodifferent heterosexual and MSM couples in which the HIV-positive partner was using suppressive ART and who reported condomless sex, during median follow-up of 1.3 years per couple, there were no documented cases of within-couple HIV transmission (upper 95% confidence limit, 0.30/100 couple-years of follow-up). Additional longer-term follow-up is necessary to provide more precise estimates of risk.
authors.affiliation: Research Department of Infection and Population Health, University College London, London, United Kingdom.
authors.forename: Alison J
authors.initials: AJ
authors.lastname: Rodger
authors.affiliation: Research Department of Infection and Population Health, University College London, London, United Kingdom.
authors.forename: Valentina
authors.initials: V
authors.lastname: Cambiano
authors.affiliation: Department of Infectious Diseases/CHIP, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Tina
authors.initials: T
authors.lastname: Bruun
authors.affiliation: Division of Infectious Diseases and Hospital Epidemiology, Cantonal Hospital, St Gallen, Switzerland.
authors.forename: Pietro
authors.initials: P
authors.lastname: Vernazza
authors.affiliation: HIV i-Base, London, United Kingdom.
authors.forename: Simon
authors.initials: S
authors.lastname: Collins
authors.affiliation: University Medical Center Hamburg-Eppendorf, Hamburg-Eppendorf, Germany.
authors.forename: Jan
authors.initials: J
authors.lastname: van Lunzen
authors.affiliation: European AIDS Treatment Group, Bruxelles, Belgium.
authors.forename: Giulio Maria
authors.initials: GM
authors.lastname: Corbelli
authors.affiliation: Hospital Clinico San Carlos and Universidad Complutense, Madrid, Spain.
authors.forename: Vicente
authors.initials: V
authors.lastname: Estrada
authors.affiliation: Institute of Infection and Global Health, University of Liverpool, Liverpool, United Kingdom.
authors.forename: Anna Maria
authors.initials: AM
authors.lastname: Geretti
authors.affiliation: Institute of Infection and Global Health, University of Liverpool, Liverpool, United Kingdom.
authors.forename: Apostolos
authors.initials: A
authors.lastname: Beloukas
authors.affiliation: Chelsea and Westminster NHS Foundation Trust, London, United Kingdom.
authors.forename: David
authors.initials: D
authors.lastname: Asboe
authors.affiliation: Hospital Virgen del Rocío, Sevilla, Spain.
authors.forename: Pompeyo
authors.initials: P
authors.lastname: Viciana
authors.affiliation: Hospital General de Elche & Universidad Miguel Hernández, Alicante, Spain.
authors.forename: Félix
authors.initials: F
authors.lastname: Gutiérrez
authors.affiliation: IrsiCaixa Foundation, UAB, UVIC-UCC, Hospital Universitari "Germans Trias i Pujol," Badalona, Catalonia, Spain.
authors.forename: Bonaventura
authors.initials: B
authors.lastname: Clotet
authors.affiliation: Department of Public Health, Nice University Hospital and EA 6312, University Nice Sophia-Antipolis, France.
authors.forename: Christian
authors.initials: C
authors.lastname: Pradier
authors.affiliation: Rigshospitalet, Copenhagen, Denmark.
authors.forename: Jan
authors.initials: J
authors.lastname: Gerstoft
authors.affiliation: Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland.
authors.forename: Rainer
authors.initials: R
authors.lastname: Weber
authors.affiliation: Unit of Infectious Diseases and Dermatology, Department of Medicine, Karolinska Institutet, and Department of Infectious Diseases, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Katarina
authors.initials: K
authors.lastname: Westling
authors.affiliation: Department of Infectious Diseases, Bern University Hospital, University of Bern, Bern, Switzerland.
authors.forename: Gilles
authors.initials: G
authors.lastname: Wandeler
authors.affiliation: Academic Medical Center, Amsterdam, the Netherlands.
authors.forename: Jan M
authors.initials: JM
authors.lastname: Prins
authors.affiliation: Medical University of Vienna, Vienna, Austria.
authors.forename: Armin
authors.initials: A
authors.lastname: Rieger
authors.affiliation: Division of Infectious Diseases and Hospital Epidemiology, University Hospital Basel, Basel, Switzerland.
authors.forename: Marcel
authors.initials: M
authors.lastname: Stoeckle
authors.affiliation: Department of Internal Medicine 1, University Hospital of Cologne, Cologne, Germany.
authors.forename: Tim
authors.initials: T
authors.lastname: Kümmerle
authors.affiliation: Ospedal San Paolo, Milan, Italy.
authors.forename: Teresa
authors.initials: T
authors.lastname: Bini
authors.affiliation: Ospedale L. Spallanzani, Roma, Italy.
authors.forename: Adriana
authors.initials: A
authors.lastname: Ammassari
authors.affiliation: Research Department of Infection and Population Health, University College London, London, United Kingdom.
authors.forename: Richard
authors.initials: R
authors.lastname: Gilson
authors.affiliation: Praxis Driesener Straße, Berlin, Germany.
authors.forename: Ivanka
authors.initials: I
authors.lastname: Krznaric
authors.affiliation: Helsinki University Central Hospital, Helsinki, Finland.
authors.forename: Matti
authors.initials: M
authors.lastname: Ristola
authors.affiliation: Medical University Innsbruck, Innsbruck, Austria.
authors.forename: Robert
authors.initials: R
authors.lastname: Zangerle
authors.affiliation: Hvidovre Universitets Hospital, Hvidovre, Denamrk.
authors.forename: Pia
authors.initials: P
authors.lastname: Handberg
authors.affiliation: Hospital Clínico Universitario de Santiago de Compostela, Santiago de Compostela, Spain.
authors.forename: Antonio
authors.initials: A
authors.lastname: Antela
authors.affiliation: Coventry and Warwickshire Hospital, Coventry, United Kingdom.
authors.forename: Sris
authors.initials: S
authors.lastname: Allan
authors.affiliation: Research Department of Infection and Population Health, University College London, London, United Kingdom.
authors.forename: Andrew N
authors.initials: AN
authors.lastname: Phillips
authors.affiliation: Department of Infectious Diseases/CHIP, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Jens
authors.initials: J
authors.lastname: Lundgren
mesh_terms: D000328:Adult; D019380:Anti-HIV Agents / Q000627:therapeutic use; D017280:Condoms; D005060:Europe; D005191:Family Characteristics; D005260:Female; D015658:HIV Infections / Q000635:transmission*; D018023:HIV Seronegativity; D006679:HIV Seropositivity; D015497:HIV-1 / Q000145:classification / Q000201:enzymology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010802:Phylogeny; D011446:Prospective Studies; D012367:RNA, Viral; D012306:Risk; D012725:Sexual Behavior; D012747:Sexual Partners; D047568:Unsafe Sex; D019562:Viral Load
chemical_list: D019380:Anti-HIV Agents; D012367:RNA, Viral