HIV-1 uninfected individuals within HIV-1 discordant partnerships are at high-risk for HIV-acquisition. The majority of HIV-1 transmissions to adults in Africa occur within stable, HIV-1 discordant couples.

Pre-exposure chemoprophylaxis, in which an HIV-1 uninfected individual at high risk for contracting HIV-1 takes antiretroviral medications to maintain blood and genital drug levels sufficient to prevent HIV-1 acquisition, has been proposed as a potential HIV-1 prevention strategy.