April 2, 2014
For people living with HIV, effective antiretroviral therapy (ART) not only suppresses the virus and protects immune system health but has the added benefit of reducing the risk of transmitting HIV to sex partners. This side benefit, known as "treatment as prevention," has been established by recent studies with mixed-HIV-status couples.
For example, in the PARTNER study, zero new HIV transmissions occurred through more than 44,000 condomless sex acts within 767 mixed-HIV-status couples in which the HIV-positive partner's viral load was suppressed below 200 copies/mL, and where the HIV-negative partner did not use PrEP or PEP to prevent infection.
Standard viral load tests look for HIV RNA (genetic material from the virus) in blood, not semen -- and the amount of RNA in these two fluids doesn't always match. And as researchers report in the March 3 online edition of PLoS ONE, not only can individuals with undetectable blood viral load have detectable levels in semen, those levels can change from hour to hour.
Xavier Ferraretto and colleagues from the Bichat-Claude Bernard Hospital in Paris looked for HIV RNA in 306 seminal plasma samples (SPSs) from 88 men enrolled in the hospital's assisted reproduction program. All participants were on ART and had undetectable blood viral load (defined here as below 50 copies/mL) for more than six months. Semen samples were obtained by masturbation after two to seven days of sexual abstinence, and each man provided, if possible, two samples within a one-hour interval.
The results? "HIV RNA was detected in at least one SPS for 17 patients (19.3%) during the study period, corresponding to 23 SPSs (7.5%)." HIV RNA levels ranged from 200 to 3,000 copies/mL, with a median (middle of the range) of 705 copies/mL.
This excerpt was cross-posted with the permission of BETAblog.org. Read the full article.