HIV Medicine, the study found that using several methods such as taking PrEP, early HIV diagnosis from frequent testing, and proper antiretroviral treatment decreased transmission by 80 percent.The research was evaluated at 56 Dean Street, which is a sexual health clinic and part of Chelsea and Westminster Hospital NHS Foundation Trust in London.“We witnessed an 80% reduction in the number of HIV diagnoses between 2012 and 2017, following the introduction of a number of HIV prevention measures (PrEP introduction, early HIV diagnosis through frequent and facilitated access to HIV testing and timely ART used as treatment-as-prevention) were key to the success of this model,” lead author Nicolo Girometti, told Contagion.