HIV May Be Present in Semen Even If Undetectable in Blood

By Liz Highleyman

The risk of HIV transmission from individuals on HAART was a topic of considerable debate at the XVII International AIDS Conference this month in Mexico City.

Earlier this year, the Swiss Federal Commission for HIV/AIDS set off the controversy when they issued a statement indicating that HIV positive individuals on antiretroviral therapy who are fully adherent, maintain an undetectable viral load (< 40 copies/mL) for at least 6 months, and have no concurrent sexually transmitted infections essentially cannot transmit HIV through heterosexual vaginal intercourse.

A new study published in the August 2008 issue of AIDS, however, indicates that HIV may remain present in a man's semen even if he has an undetectable blood plasma viral load.

Anne-Genevieve Marcelin and colleagues analyzed paired semen and plasma samples collected between January 2002 and January 2008 from 145 HIV positive men enrolled in an assisted reproduction program at Pitié-Salpêtrière Hospital in Paris, France. The program used "sperm washing" -- a procedure that separates HIV infected from uninfected sperm -- to help serodiscordant couples safely conceive.

Over time, the men provided a total of 264 paired samples (1-6 samples per participant). The investigators used a test with a lower limit of detection of 40 copies/mL in blood plasma (the cut-off specified in the Swiss statement) and 200 copies/mL in semen.

Results

• In 85% of the paired samples, HIV was not detectable in either semen or blood plasma.

• 3% of the paired samples revealed detectable HIV RNA in both semen and blood.

• 6% of samples revealed detectable HIV in blood but not semen.

• 5% of the men had detectable HIV in their semen, even though they had no other sexually transmitted disease and had undetectable plasma viral load for at least 6 months on antiretroviral therapy.

• All 7 of these men also had some semen samples with undetectable HIV, indicating that the presence of virus fluctuated over time.

These findings, the study authors concluded, justify measuring HIV RNA in semen before the assisted reproduction process, and suggest that "a residual risk of transmission has to be mentioned to the patients who would like to have unprotected sexual intercourse."

In their article they wrote, "We agree [with the Swiss commission] that the risk of HIV transmission in this particular case is very low. However, several factors can interfere and may have the potential to increase this risk, such as fluctuation of adherence, drug characteristics influencing the penetration in compartments, and asymptomatic and undiagnosed sexually transmitted disease."

They added that given the "certainly low, but not null, risk of transmission" for serodiscordant couples, assisted reproduction technology such as sperm washing "remains a preferred method, when accessible, to avoid HIV transmission."

8/29/08

Reference
AG Marcelin, R Tubiana, S Lambert-Niclot, and others. Detection of HIV-1 RNA in seminal plasma samples from treated patients with undetectable HIV-1 RNA in blood plasma. AIDS 22(13): 1677-1679. August 2008.