Answer: In 2011, the HIV Prevention Trials Network (HPTN 052) study demonstrated that the use of ARVs by HIV-positive heterosexual men and women cut the chance that their HIV-negative partner would contract the virus by roughly 96%. HPTN 052 and other studies prove that people living with HIV on effective treatment do not sexually transmit the virus, which is known as U=U, or Undetectable Equals Untransmittable.