HIV treatment as prevention: Natural experiments highlight limits of antiretroviral treatment as HIV prevention

There is growing enthusiasm for increasing coverage of antiretroviral treatment among hiv-infected people for the purposes of preventing ongoing transmission. treatment as prevention will face a number of barriers when implemented in real world populations,which will likely lead to the effectiveness of this strategy being lower than proposed by optimistic modelling scenarios or ideal clinical trial settings. some settings,as part of their prevention and treatment strategies,have already attained rates of hiv testing and use of antiretroviral therapy-with high levels of viral suppression-that many countries would aspire to as targets for a treatment-as-prevention strategy. this review examines a number of these natural experiments