Pre-exposure prophylaxis (PrEP) in HIV-uninfected individuals with high-risk behaviour

The global incidence of human immunodeficiency virus (HIV) infection has decreased by 15% over the past years, but is still too high. Despite current programs to reduce the incidence of HIV infection, further approaches are needed to limit this epidemic. Oral antiretroviral pre-exposure prophylaxis (PrEP) is currently one of the most discussed possible prevention methods. This literature study demonstrates whether orally antiretroviral chemoprophylaxis in HIV-uninfected individuals with high-risk behaviour reduces the transmission of HIV. We used the PICO method and conducted a search to identify relevant studies. Subjects of the study were HIV-uninfected individuals with high-risk behaviour. Intervention was oral PrEP with tenofovir disoproxil fumarate (TDF) alone or plus emtricitabine (FTC) versus placebo. The primary outcome was the HIV incidence among this high-risk group. Secondary outcomes were adherence to PrEP, frequency and type of adverse effects. We identified ten studies from which five randomised control trials (RCTs) were included after screening. The results from three out of five trials showed a reduction, but two trials showed no protection in acquiring HIV infection. There were no significant differences in adverse events. The adherence was different among different groups and affected the outcome of the studies. In conclusion, this prophylaxis might offer protection when used in combination with intense monitoring and guidance in uninfected individuals with a high risk of HIV acquisition. However, there are still many unresolved questions. Drug adherence seems to be a crucial factor in the effectiveness of PrEP. Therefore, individual risk behaviour remains an important determinant for success in the prevention of HIV transmission.