Section 5: Post-exposure prophylaxis (PEP)

Viral load and risk of heterosexual transmission

  • Viral load is the chief predictor of the risk of heterosexual transmission of HIV-11
  • Transmission is rare when levels <1500 copies/mL1,2
  • Studies of heterosexual discordant couples observed no transmission in patients treated with ART and with viral load <400 copies/mL2
    • Data were compatible with one transmission per 79 person-years2
  • Swiss consensus states: “An HIV-infected person on antiretroviral therapy with completely suppressed viraemia (“effective ART”) is not sexually infectious”3

1. Quinn TC, et al. N Engl J Med 2000;342:921–29.
2. Attia S, et al. AIDS 2009;23:1397–404.
3. Vernazza P, et al. Bull Med Suisses 2008;89:165–69.