An HIV-positive man with an undetectable viral load in his blood continued to have detectable levels of HIV in his semen, French doctors report in the September 12th edition of AIDS.
This case report will further inform discussions about the infectiousness of patients taking antiretroviral therapy prompted by the “Swiss Statement” in January. Other investigators have recently found an apparent case of HIV transmission involving a patient taking antiretroviral therapy who had an undetectable viral load. A separate French study found that approximately 5% of patients with an undetectable viral load in their blood had HIV present in their semen. But US investigators found no cases of HIV transmission involving patients taking antiretroviral therapy with an undetectable viral load, and that when transmission did occur, it was related to viral load in blood rather than semen.
The current case involved an HIV-positive man who was receiving treatment at an assisted conception clinic. In June 2006, he started antiretroviral therapy with a regimen that included AZT, 3TC and fosamprenavir/ritonavir. His blood viral load fell to undetectable levels four months later, but viral load in his semen remained detectable.
In May 2007 the patient’s antiretroviral treatment was changed to FTC, tenofovir and lopinavir/ritonavir. The viral load in his blood remained undetectable, but after six months of this new treatment HIV remained detectable in his semen.
After eleven months of treatment with this second regimen viral load in the patient’s semen slowly declined to below 400 copies/ml.
The investigators could find no obvious reason why viral load had remained detectable for so long in the patient’s semen. There was no evidence of resistance to antiretroviral drugs in either the patient’s blood or semen. Nor did the patient have any sexually transmitted infections. Furthermore, the patient’s adherence to antiretroviral therapy appeared good, with blood viral load measurement over a two year period being undetectable.
“This case report confirms that highly active antiretroviral therapy may act at different rates in the blood and semen and that HIV may continue to be shed into the semen despite effective control of HIV in the blood”, write the investigators.
Poor penetration of antiretroviral drugs into the genital tract is thought by the investigators to be the likely explanation why HIV remained detectable in the patient’s semen for such a protracted period. In March 2008, ten months after treatment with the second regimen was started, only lopinavir/ritonavir could be detected in the man’s semen.
“Counselling on the prevention of sexual transmission should include the possibility of occult persistent HIV replication within the genital tract”, conclude the investigators.
Pasquier C J-M et al. Persistent differences in the antiviral effects of highly active antiretroviral therapy in the blood and male genital tract. AIDS 22: 1894 – 95, 2008.