HIV pre-exposure prophylaxis (PrEP), the use of antiretroviral drugs by uninfected individuals to prevent HIV infection, has demonstrated effectiveness in preventing acquisition in a high-risk population of men who have sex with men (MSM).

Researchers from the Imperial College London have developed a mathematical model representing the HIV epidemic among MSM and transwomen (male-to-female transgender individuals) in Lima, Peru, to investigate how PrEP can be used cost-effectively to prevent HIV infection in such populations.

The study reported that strategic PrEP intervention could be a cost-effective addition to existing HIV prevention strategies for MSM populations.

However, PrEP will not arrest HIV transmission in isolation because of its incomplete effectiveness and dependence on adherence, and because the high cost of programmes limits the coverage levels that could potentially be attained.