SOURCE: Rodger AJ, Cambiano V, Bruun T, et al. Sexual activity without condoms and risk of HIV transmission in serodifferent couples when the HIV-positive partner Is using suppressive antiretroviral therapy. JAMA 2016;316:171-181.

Prevention of seroconversion in HIV serodiscordant couples (in which one partner is HIV positive and the other is not) is reduced by using barrier methods, especially when the HIV-positive partner is receiving antiretroviral therapy (ART). ART provides sustained reductions in HIV viral load and reduced infectivity, but would it be safe for serodiscordant couples to omit barrier methods entirely?

Rodger et al performed a prospective observational study (n = 888) of serodiscordant sexually active heterosexuals, men who have sex with men (MSM), and gay couples. The HIV-positive partners all were receiving ART, and > 80% presented with undetectable levels of HIV virus (some subjects on ART did not report viral load status, but are presumed to be similarly undetectable). Couples agreed to abstain from barriers during intravaginal or intra-anal intromission.

During 1.3 years (mean) of follow-up, there were no confirmed HIV conversions; any new HIV conversions were found to be from HIV strains not harbored by the HIV-positive partner and must have occurred from another external HIV-positive source.

Since intra-anal transmission is more common than intravaginal transmission, it is particularly welcome that the rate of conversion was zero among all participants, including the 340 MSM.