title: Transmission probabilities of HIV and herpes simplex virus type 2, effect of male circumcision and interaction: a longitudinal study in a township of South Africa.
abstract: OBJECTIVE
  A synergy between HIV and herpes simplex virus type 2 (HSV-2) infections has been reported in observational studies. The objectives of this study were to estimate the per-sex-act female-to-male transmission probabilities (FtoMTPs) of HIV and HSV-2, the effect of each infection on the FtoMTP of the other and the effect of male circumcision on these FtoMTPs.
  
  
  METHODS
  We used longitudinal data collected during the male circumcision trial conducted in Orange Farm (South Africa).
  
  
  METHODS
  Results were obtained by specific mathematical modeling of HIV and HSV-2 statuses of the men as functions of their sexual behavior and male circumcision status. The model took into account an estimation of the HIV and HSV-2 statuses of each of their female partners. Confidence intervals (CI) were estimated using a bootstrap resampling method.
  
  
  RESULTS
  The HIV and HSV-2 FtoMTPs, during an unprotected sexual contact for an uncircumcised male in the absence of the other virus in both partners, were 0.0047 (95% CI: 0.0014-0.017) and 0.0067 (95% CI: 0.0028-0.014), respectively. HSV-2 in either partner increased HIV FtoMTP with a relative risk (RR) of 3.0 (95% CI: 1.01-7.3). Conversely, HIV in either partner increased HSV-2 FtoMTP (RR= 2.5; 95% CI: 1.1- 6.3). Male circumcision significantly decreased these probabilities with RRs of 0.24 (95% CI: 0.11-0.44) and 0.59 (95% CI: 0.36-0.91), respectively.
  
  
  CONCLUSIONS
  This study gave the first estimates of HSV-2 per-sex-act FtoMTPs in Africa. It demonstrated a synergy between HIV and HSV-2 infections and a protective effect of male circumcision on HSV-2 acquisition by males.
authors.affiliation: Ecole Nationale Supérieure Polytechnique de Yaoundé, Cameroon, South Africa.
authors.forename: Severin-Guy
authors.initials: SG
authors.lastname: Mahiane
authors.forename: Camille
authors.initials: C
authors.lastname: Legeai
authors.forename: Dirk
authors.initials: D
authors.lastname: Taljaard
authors.forename: Aurelien
authors.initials: A
authors.lastname: Latouche
authors.forename: Adrian
authors.initials: A
authors.lastname: Puren
authors.forename: Aurelie
authors.initials: A
authors.lastname: Peillon
authors.forename: Jean
authors.initials: J
authors.lastname: Bretagnolle
authors.forename: Pascale
authors.initials: P
authors.lastname: Lissouba
authors.forename: Eugene-Patrice Ndong
authors.initials: EP
authors.lastname: Nguema
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Gassiat
authors.forename: Bertran
authors.initials: B
authors.lastname: Auvert
mesh_terms: D000293:Adolescent; D002944:Circumcision, Male / Q000706:statistics & numerical data*; D005260:Female; D015658:HIV Infections / Q000453:epidemiology / Q000517:prevention & control / Q000635:transmission*; D006558:Herpes Genitalis / Q000453:epidemiology / Q000517:prevention & control / Q000635:transmission*; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D012307:Risk Factors; D012725:Sexual Behavior / Q000706:statistics & numerical data; D013019:South Africa / Q000453:epidemiology; D055815:Young Adult