Pre-exposure prophylaxis for HIV infection

Clinical trials of pre-exposure prophylaxis - that is giving anti-retroviral drugs to non-HIV-infected individuals to prevent them becoming infected - are exploring whether the approach could lead to a large decrease in transmission of the virus with few or no side effects.

However implementation of a pre-exposure prophylaxis programme, if the intervention is proven effective, will require careful planning and substantial resources.

These issues are discussed in a Viewpoint in this week's edition of The Lancet.

Several phase II and III trials of anti-retroviral drug combinations such as tenofovir and emtricitabine are being studied among various at-risk populations, including men who have sex with men, injecting-drug users, and heterosexual men and women.

Dr Lynn Paxton, Centers for Disease Control and Prevention, Atlanta, Georgia, USA and colleagues discuss the implementation issues that will need to be addressed including: ensuring access to those at risk; minimizing potential increases in risk behaviour; and minimizing the possibility of development of drug resistant forms of the virus. The authors argue that because efficacy results from the ongoing studies may be available as early as 2008, preliminary planning for implementation should start now.