The use of highly active antiretroviral therapy (HAART) as a strategy to prevent the transmission of HIV infection is of substantial international interest. Injection drug users (IDUs) are an important population with respect to HIV treatment as prevention because they are often less likely to access HAART in comparison with other risk groups.
A recent multicentre randomized clinical trial demonstrated a 96% reduction in HIV transmission among heterosexual serodiscordant couples prescribed early HAART. Consistent with these results, independent observational studies from Baltimore and Vancouver have demonstrated that population level rates of HAART use among IDUs are associated with reduced rates of HIV incidence. In addition, impact assessments of HAART delivery to IDUs have generally demonstrated no negative effects of HAART use on rates of unsafe sex or syringe sharing.
HAART prevents HIV transmission because it dramatically decreases HIV-1 RNA levels in biological fluids. This is relevant to vertical and sexual HIV transmission and also to blood-borne HIV transmission, as it is often the case among IDUs. Efforts to expand HAART to IDUs should be redoubled in an effort to realize both the individual and public health benefits of HAART.