title: Circumcision status and HIV infection among MSM: reanalysis of a Phase III HIV vaccine clinical trial.
abstract: OBJECTIVE
  Determine whether male circumcision would be effective in reducing HIV transmission among men who have sex with men (MSM).
  
  
  METHODS
  Retrospective analysis of the VAXGen VAX004 HIV vaccine clinical trial data.
  
  
  METHODS
  Survival analysis was used to associate time to HIV infection with multiple predictors. Unprotected insertive and receptive anal sex predictors were highly correlated, thus separate models were run.
  
  
  RESULTS
  Four thousand eight hundred and eighty-nine participants were included in this reanalysis; 86.1% were circumcised. Three hundred and forty-two (7.0%) men became infected during the study; 87.4% were circumcised. Controlling for demographic characteristics and risk behaviors, in the model that included unprotected insertive anal sex, being uncircumcised was not associated with incident HIV infection [adjusted hazards ratio (AHR) = 0.97, confidence interval (CI) = 0.56-1.68]. Furthermore, while having unprotected insertive (AHR = 2.25, CI = 1.72-2.93) or receptive (AHR = 3.45, CI = 2.58-4.61) anal sex with an HIV-positive partner were associated with HIV infection, the associations between HIV incidence and the interaction between being uncircumcised and reporting unprotected insertive (AHR = 1.78, CI = 0.90-3.53) or receptive (AHR = 1.26, CI = 0.62-2.57) anal sex with an HIV-positive partner were not statistically significant. Of the study visits when a participant reported unprotected insertive anal sex with an HIV-positive partner, HIV infection among circumcised men was reported in 3.16% of the visits (80/2532) and among uncircumcised men in 3.93% of the visits (14/356) [relative risk (RR) = 0.80, CI = 0.46-1.39].
  
  
  CONCLUSIONS
  Among men who reported unprotected insertive anal sex with HIV-positive partners, being uncircumcised did not confer a statistically significant increase in HIV infection risk. Additional studies with more incident HIV infections or that include a larger proportion of uncircumcised men may provide a more definitive result.
authors.affiliation: HIV Vaccine and Special Studies Team, Epidemiology Branch, Division of HIV/AIDS Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA. dgust@cdc.gov
authors.forename: Deborah A
authors.initials: DA
authors.lastname: Gust
authors.forename: Ryan E
authors.initials: RE
authors.lastname: Wiegand
authors.forename: Katrina
authors.initials: K
authors.lastname: Kretsinger
authors.forename: Stephanie
authors.initials: S
authors.lastname: Sansom
authors.forename: Peter H
authors.initials: PH
authors.lastname: Kilmarx
authors.forename: Brad N
authors.initials: BN
authors.lastname: Bartholow
authors.forename: Robert T
authors.initials: RT
authors.lastname: Chen
mesh_terms: D016915:AIDS Vaccines / Q000008:administration & dosage*; D000328:Adult; D017326:Clinical Trials, Phase III as Topic; D015658:HIV Infections / Q000453:epidemiology / Q000517:prevention & control* / Q000635:transmission; D006801:Humans; D007407:Interviews as Topic; D008297:Male; D010342:Patient Acceptance of Health Care / Q000706:statistics & numerical data*; D012189:Retrospective Studies; D012307:Risk Factors; D012309:Risk-Taking; D012725:Sexual Behavior; D012749:Sexually Transmitted Diseases / Q000453:epidemiology / Q000517:prevention & control* / Q000635:transmission
chemical_list: D016915:AIDS Vaccines