An HIV prevention strategy in which people at risk of becoming exposed to HIV take antiretroviral drugs to reduce their chance of becoming infected (often referred to as pre-exposure prophylaxis or PrEP), may be a cost-effective method of preventing HIV in some settings, according to a study by international researchers published in this week's PLOS Medicine.

In an analysis of 13 modelling studies led by Gabriela Gomez from the Department of , Academic Medical Centre, University of Amsterdam/AIGHD in The Netherlands, the authors evaluated the impact of pre-exposure prophylaxis in different populations (, men who have sex with men, and people who inject drugs) in different regions and countries, such as , Ukraine, the US, and Peru.

They found that in every setting, the cost of was an important factor influencing the affordability of effective prevention programmes but delivery of pre-exposure prophylaxis to populations at higher risk of HIV exposure appeared to be the most cost-effective strategy. The authors also found that both behavioural changes and adherence to the pre-exposure prophylaxis drug regimens affected programme effectiveness.

The authors say: "Our findings show that pre-exposure prophylaxis has the potential to be a cost-effective addition to HIV prevention programmes in some settings."

They continue: "However, the cost-effectiveness of pre-exposure prophylaxis is likely to depend on considerations such as cost, the epidemic context, pre-exposure prophylaxis programme coverage and prioritisation strategies, as well as individual adherence levels and pre-exposure prophylaxis efficacy estimates."

The authors add: "Given that our review shows that both the setting and which population is prioritised for pre-exposure prophylaxis are critical drivers of cost-effectiveness, the next step is to conduct context-specific demonstration studies, including comprehensive cost analyses, of different prioritisation and adherence promotion strategies to ensure that the maximum benefit from the introduction of pre-exposure prophylaxis is realised within combination HIV prevention programmes."

More information: Gomez GB, Borquez A, Case KK, Wheelock A, Vassall A, et al. (2013) The Cost and Impact of Scaling Up Pre-exposure Prophylaxis for HIV Prevention: A Systematic Review of Cost-Effectiveness Modelling Studies. PLoS Med 10(3): e1001401. doi:10.1371/journal.pmed.1001401

Journal information: PLoS Medicine