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Early Treatment of an HIV-Infected Person Reduces the Rate of HIV Transmission to an Uninfected Partner

Recent findings from international clinical studies have led NIAID to investigate early treatment of HIV infection as a way to prevent the spread of the virus from HIV-infected individuals to their uninfected partners. To capitalize on recent successes, NIAID-funded scientists tested this approach in more than 1,700 couples where one partner was HIV positive. Couples from nine countries were included in the study, and 97 percent of the couples were heterosexual.

HIV-infected patients were randomly assigned into one of two treatment groups based on a common indicator of HIV disease progress: the reduction in numbers of CD4 T cells in the blood. These cells are the primary immune cell targeted by HIV and range between 500 to 1,500 cells per cubic milliliter of blood in healthy people. Patients enrolled in the early-therapy group received antiretroviral therapy (ART) when their CD4 counts fell to between 350 and 550. Those in the delayed-therapy group did not receive ART until their counts fell below 250 or when HIV-related symptoms developed.

At the end of the study, 39 cases of HIV transmission were reported among the study participants, and 28 of these people were infected with viruses that were genetically linked to their infected partner. Importantly, only one case of infection occurred in the early-therapy group. Furthermore, patients receiving early treatment were less likely to develop serious signs of HIV infection. In accord with previous studies, this study showed that early treatment of an HIV-infected partner in a couple reduces the rate of sexual transmission of HIV and clinical problems associated with infection.


Cohen MS, Chen YQ, McCauley M, Gamble T, Hosseinipour MC, Kumarasamy N, Hakim JG, Kumwenda J, Grinsztejn B, Pilotto JH, Godbole SV, Mehendale S, Chariyalertsak S, Santos BR, Mayer KH, Hoffman IF, Eshleman SH, Piwowar-Manning E, Wang L, Makhema J, Mills LA, de Bruyn G, Sanne I, Eron J, Gallant J, Havlir D, Swindells S, Ribaudo H, Elharrar V, Burns D, Taha TE, Nielsen-Saines K, Celentano D, Essex M, Fleming TR; HPTN 052 Study Team. Prevention of HIV-1 infection with early antiretroviral therapy. N Engl J Med. 2011 Aug 11;365(6):493-505.

Image of a healthy human T cell
A healthy human T cell
Credit: NIAID

Last Updated December 28, 2012