Men more frequently have detectable HIV in their sexual fluids than women, meaning that men, even when taking highly active antiretroviral therapy (HAART) that is successfully controlling viral load in the blood, could be more infectious than women, according to an American study presented to the 44th Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC) in Washington this week.
Investigators examined semen samples obtained from 63 men, cervical fluid and cervicovaginal lavage obtained from women. Seventy-four women provided specimens of cervical fluid and 80 women provided cervicovaginal lavage. Saliva samples were also obtained. The samples were obtained on entry to the AIDS Clinical Trials Group (ACTG) A5077 study, which is designed to evaluate the characteristics of HIV in blood and other compartments in men and women starting or changing HAART.
The study will last for 96 weeks and is longitudinal in design. It has recruited a total of 86 men and 87 women from several treatment centres.
In the current baseline anaylsis, individuals had a median age of 41 years, and had taken a median of five previous antiretroviral drugs. The median CD4 cell count was 210 cells/mm3 and median viral load in blood plasma was 10 copies/ml.
All patients had detectable viral load in their blood plasma, and the investigators found a weak correlation between viral load in blood plasma and virus in seminal plasma (r = 0.24), cervical fluid (r = 0.32), and cervicovaginal lavage (r = 0.31). No difference was found in the frequency of HIV shedding in saliva between the sexes.
Genital shedding of HIV was significantly more common in men than women who were taking HAART (70 vs. 26%), or were not currently taking antiretroviral therapy (82 vs. 38%).
When the investigators adjusted viral load for CD4 cell count and gender they found that viral load was 0.17 log10 copies/ml lower in women than men.
The investigators conclude, “sex differences were noted with more men than women having detectable HIV in genital fluids, which suggests that on or off antiretroviral therapy, men may be more infectious than women.”
Coombs RW et al. A comparison of HIV-1 level in blood and non-blood compartments between men and women: baseline analysis of ACTG protocol A5077. 44th Interscience Conference on Antimicrobial Agents and Chemotherapy, Washington, abstract H-198, 2004.