Impact Of Pre-exposure Prophylaxis Research Articles

HIV Pre-exposure Prophylaxis: Clinical Implications and Real-World Effectiveness

The use of tenofovir-emtricitabine as pre-exposure prophylaxis (PrEP) represents the latest strategy to prevent the acquisition of HIV by uninfected individuals. Despite clinical trials exhibiting significant risk reductions with PrEP, several limitations may hinder its real-world effectiveness. PrEP functions as one component of a comprehensive prevention program, which should also include intensive counseling on the importance of adherence, reduction of high-risk behaviors, and continued use of traditional preventative methods. Additionally, the greatest impact of PrEP, both clinically and financially, will likely arise from careful application in select high-risk populations. If properly implemented, PrEP has the potential to significantly reduce the incidence of new HIV infections.

LBO-1.2 The potential impact of pre-exposure prophylaxis for HIV prevention among Men who Have Sex with Men (MSM) in Lima, Peru

BackgroundHIV Pre-exposure prophylaxis (PrEP), the use of antiretroviral drugs by those HIV uninfected individuals to prevent HIV infection, recently demonstrated effectiveness in preventing acquisition in a high risk population of...

O1-S06.02 Impact of pill sharing on drug-resistance and population-level effectiveness of a wide-scale oral PrEP intervention in resource-constrained settings

BackgroundIn 2010 two randomised trials suggested that pre-exposure prophylaxis (PrEP) products based on tenofovir, an antiretroviral drug either administered daily orally (oral PrEP) or applied topically (vaginal microbicides), significantly reduced...

Factors Influencing the Emergence and Spread of HIV Drug Resistance Arising from Rollout of Antiretroviral Pre-Exposure Prophylaxis (PrEP)

BackgroundThe potential for emergence and spread of HIV drug resistance from rollout of antiretroviral (ARV) pre-exposure prophylaxis (PrEP) is an important public health concern. We investigated determinants of HIV drug resistance prevalence after PrEP implementation through mathematical modeling.MethodologyA model incorporating heterogeneity in age, gender, sexual activity, HIV infection status, stage of disease, PrEP coverage/discontinuation, and HIV drug susceptibility, was designed to simulate the impact of PrEP on HIV prevention and drug resistance in a sub-Saharan epidemic.Principal FindingsAnalyses suggest that the prevalence of HIV drug resistance is influenced most by the extent and duration of inadvertent PrEP use in individuals already infected with HIV. Other key factors affecting drug resistance prevalence include the persistence time of transmitted resistance and the duration of inadvertent PrEP use in individuals who become infected on PrEP. From uncertainty analysis, the median overall prevalence of drug resistance at 10 years was predicted to be 9.2% (interquartile range 6.9%–12.2%). An optimistic scenario of 75% PrEP efficacy, 60% coverage of the susceptible population, and 5% inadvertent PrEP use predicts a rise in HIV drug resistance prevalence to only 2.5% after 10 years. By contrast, in a pessimistic scenario of 25% PrEP efficacy, 15% population coverage, and 25% inadvertent PrEP use, resistance prevalence increased to over 40%.ConclusionsInadvertent PrEP use in previously-infected individuals is the major determinant of HIV drug resistance prevalence arising from PrEP. Both the rate and duration of inadvertent PrEP use are key factors. PrEP rollout programs should include routine monitoring of HIV infection status to limit the spread of drug resistance.

Circulating HIV Type 1 Drug Resistance Will Have Limited Impact on the Effectiveness of Preexposure Prophylaxis among Young Women in Zimbabwe

Preexposure prophylaxis (PrEP) with antiretroviral drugs may prevent transmission of human immunodeficiency virus (HIV). Our objective was to predict whether PrEP, in the presence of circulating drug resistance, will reduce the risk of infection with HIV. We used risk equations to calculate the monthly risk of infection with HIV before and after the introduction of PrEP. Uncertainty and sensitivity analyses were performed for 2 ranges of PrEP effectiveness (40%-60% and 60%-80%). Circulating drug resistance was assumed to reduce the effectiveness of PrEP by 50%-90% and the transmissibility of HIV by 0%-30%. Parameter ranges were chosen for women 17-29 years of age from publications on HIV in Manicaland in Zimbabwe. PrEP would decrease the median risk of HIV transmission by 21%-33% (effectiveness of PrEP, 40%-60% and 60%-80%). If 50% of HIV strains are drug resistant, then the median risk reduction would be 19%-26% if drug-resistant strains were less transmissible than wild-type HIV and 12%-19% if they were equally transmissible. The risk would increase if condoms were frequently replaced with PrEP. Use of PrEP for sexual acts for which no protection is currently used would be beneficial. The public health impact of PrEP will depend on its effectiveness and on risk behavior. Circulating drug resistance will have only a small impact on the effectiveness of PrEP.

The impact of pre-exposure prophylaxis (PrEP) on HIV epidemics in Africa and India: a simulation study.

BackgroundPre-exposure prophylaxis (PrEP) is a promising new HIV prevention method, especially for women. An urgent demand for implementation of PrEP is expected at the moment efficacy has been demonstrated in clinical trials. We explored the long-term impact of PrEP on HIV transmission in different HIV epidemics.Methodology/Principal FindingsWe used a mathematical model that distinguishes the general population, sex workers and their clients. PrEP scenarios varying in effectiveness, coverage and target group were modeled in the epidemiological settings of Botswana, Nyanza Province in Kenya, and Southern India. We also studied the effect of condom addition or condom substitution during PrEP use. Main outcome was number of HIV infections averted over ten years of PrEP use. PrEP strategies with high effectiveness and high coverage can have a substantial impact in African settings. In Southern India, by contrast, the number of averted HIV infections in different PrEP scenarios would be much lower. The impact of PrEP may be strongly diminished or even reversed by behavioral disinhibition, especially in scenarios with low coverage and low effectiveness. However, additional condom use during low coverage and low effective PrEP doubled the amount of averted HIV infections.Conclusions/SignificanceThe public health impact of PrEP can be substantial. However, this impact may be diminished, or even reversed, by changes in risk behavior. Implementation of PrEP strategies should therefore come on top of current condom campaigns, not as a substitution.