Study: Antiretroviral therapy cuts HIV transmission risk by 96%

WASHINGTON — Patients with HIV who immediately started antiretroviral therapy significantly reduced the risk of spreading the virus to an uninfected partner, compared with those who delayed therapy, according to results of a multinational study. The study also found that antiretroviral therapy reduced the risk of transmission by 96%.

The six-year “HPTN 052” ”study, conducted by the HIV Prevention Trials Network at 13 sites in the Americas, Asia and Africa, enrolled 1,763 couples in which one partner was HIV-positive and the other was HIV-negative — also known as serodiscordant couples — 97% of which were heterosexual. The infected partner had to have a CD4 cell count of 350 to 550 per cubic millimeter at level, at which he or she did or did not yet require HIV treatment. Researchers then divided couples into two groups, one in which the infected partner immediately started therapy, and another in which the partner delayed therapy until after his or her CD4 count began decreasing.

Among the 877 couples in the delayed-treatment group, there were 27 cases of the uninfected partner contracting HIV, but in the immediate-treatment group, only one infection occurred.

“This is excellent news,” principle study investigator and associate vice chancellor for global health and director of the Institute of Global Health and Infectious Diseases at the University of North Carolina at Chapel Hill Myron Cohen said. “The study was designed to evaluate the benefit to the sexual partner as well as the benefit to the HIV-infected person. This is the first randomized clinical trial to definitively indicate that an HIV-infected individual can reduce sexual transmission of HIV to an uninfected partner by beginning antiretroviral therapy sooner.”