This review of available studies concluded that antiretroviral therapy may prevent sexual transmission of HIV in discordant couples. The authors identified seven studies that examined the effects of antiretroviral treatment among HIV positive individuals in heterosexual and same-sex HIV-discordant partnerships. The studies that the authors used for their analysis had been conducted in Italy, Brazil, Zambia, Uganda, Rwanda, Tanzania, South Africa, Botswana, Kenya, Spain, and China.
Within these seven studies, there were 436 episodes of HIV transmission- 71 among couples in which the HIV positive individual was receiving antiretroviral treatment and 365 among couples in which there was no treatment. The authors found that in couples in which the HIV positive partner was receiving antiretroviral treatment, the partners without HIV had more than 5-times lower risk of being infected than in couples where the HIV positive partner was not receiving treatment. While this analysis should not be read to imply that it is impossible for such transmission to occur, it does suggest that antiretroviral treatment can significantly lower the rate of sexual transmission in HIV-discordant couples.