International AIDS Society

HIV Detectable in Semen But Not Blood of ART-Treated US MSM

Author: Mark Mascolini

14 August 2012

HIV remained detectable in 25% of men who have sex with men (MSM) taking antiretroviral therapy (ART) that made HIV undetectable in blood. This finding from a US clinic underlines the possible risk of HIV transmission from MSM with an undetectable viral load in blood.

Combination ART suppresses genital HIV shedding and sharply lowered risk of HIV transmission HPTN 052, a randomized trial of immediate versus delayed ART. Despite wide use of ART by HIV-positive MSM in many countries, HIV rates often remain high in this population.

US researchers hypothesized that unsafe sex, sexually transmitted infections (STIs), and other factors may promote seminal HIV shedding and transmission in MSM despite ART. They planned this study to determine prevalence of seminal HIV shedding in MSM on stable ART and to identify shedding risk factors.

The study involved 101 MSM recruited from an MSM health clinic. Men gave semen and blood samples for paired HIV RNA assessment. Researchers also determined herpes simplex virus 2 serostatus, seminal HSV-2 DNA levels, and markers of genital inflammation. Medical records and questionnaires provided clinical and behavioral data.

Of the 101 men studied, 18 (18%) had detectable HIV RNA in blood and 30 (30%) had detectable HIV RNA in semen. Among 83 men with undetectable HIV RNA in blood, 21 (25%) had detectable HIV RNA in semen, with copy numbers ranging from 80 to 2560.

Multivariate analysis identified three factors that independently predicted detection of HIV RNA in semen: an STI or urethritis (P  =  0.003), tumor necrosis factor alpha (P  =  0.0003), and unprotected insertive anal sex with an HIV-positive partner (P  =  0.007).

Earlier, a 304-man 2002-2011 study in France found that 20 men (6.6%) with an undetectable viral load in blood had detectable viral load in semen (Lambert-Niclot S et al. AIDS. 2012; 26: 971-975).

The US researchers concluded that “STIs and genital inflammation can partially override the suppressive effect of HAART on seminal HIV shedding in sexually active HIV-infected MSM.”

They warn that “low seminal HIV titers could potentially pose a transmission risk in MSM, who are highly susceptible to HIV infection.”

Source: Joseph A. Politch, Kenneth H. Mayer, Seth L. Welles, William X. O’Brien, Chong Xu, Frederick P. Bowman, Deborah J. Anderson. Highly active antiretroviral therapy does not completely suppress HIV in semen of sexually active HIV-infected men who have sex with men. AIDS. 2012; 26: 1535-1543.

For the study abstract

(Downloading the complete article requires a subscription to AIDS or an online payment; the abstract is free.)