Men taking virologically suppressive ART have undetectable HIV in their pre-ejaculatory fluid

HIV is undetectable in the pre-ejaculatory fluid of men taking suppressive antiretroviral therapy, investigators from the United States report in the online edition of AIDS. Approximately a fifth of men with an undetectable viral load in their blood had low-level HIV replication in their semen, but none were shedding virus in pre-ejaculate.

“Our study provides the first evidence that pre-ejaculatory sexual secretions in men on [ART], unlike those from untreated men, do not contain detectable HIV,” comment the investigators.

There is now overwhelming evidence that men and women who are taking stable ART that suppresses HIV in blood to undetectable levels are extremely unlikely to transmit the virus to their sexual partners. However, persistent HIV replication has been detected in the semen of men taking treatment that suppresses viral load in blood.

HIV has been detected in the pre-ejaculatory fluid – colloquially called pre-cum – of HIV-infected men not on ART and also in pre-ejaculatory samples obtained from ART-exposed monkeys. Pre-ejaculate is thought to be a possible source of HIV transmission.

Investigators in Boston wanted to see if HIV-replication persists in pre-ejaculatory fluid in the context of treatment that suppresses viral load in blood and also to establish if there is a relationship between detectable viral load in semen and viral shedding in pre-ejaculate.

Their study sample comprised 60 men. All were sexually active and had been taking a stable antiretroviral regimen for at least three months.

Samples of pre-ejaculate, semen and blood were provided for viral load quantification. The men were also screened for urethral sexually transmitted infections (STIs), urethritis and HSV infections.

Eight of the men had detectable viral load in their blood (range, 80-640,000 copies/ml) and were excluded from the principal analysis.

The remaining 52 men all had blood viral load below the limit of detection (40 copies/ml). Their median age was 43 years, median CD4 cell count was 518 cells/mm³, 96% reported sex with other men, and 44% said they had had insertive unprotected anal sex within the past three months. None of the patients had a bacterial urethral STI, one had urethritis and one was shedding HSV-2 in semen.

Four of the men with detectable HIV in their blood were also shedding virus in their semen, viral load ranging between 40 and 96,000 copies/ml. One man in this group also had detectable virus in his pre-ejaculate (2,400 copies/ml).

Of the 52 men with undetectable viral load in their blood, ten (19%) had low level HIV replication in their semen (59 to 800 copies/ml). However, none had virus in their pre-ejaculatory fluid.

Both the patients with urethritis and the individual with seminal HSV-2 both had detectable HIV in their semen.

“Although HIV-1 RNA was detected in semen of men on stable ART with undetectable blood viral load, it was not detected in pre-ejaculatory secretions,” conclude the authors. “These data indicate that pre-ejaculatory fluid may not contribute to HIV transmission in men on ART, at least in men without genital infections.”