Undetectable HIV Viral Load May Encourage Risky Sex

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By David Douglas

In male couples of whom only one partner is HIV positive, unprotected anal intercourse (UAI) is significantly more likely if the positive partner has undetectable viral load, Australian researchers report in the January 28th issue of AIDS.

Nevertheless, Dr. Limin Mao of the University of New South Wales, Sydney and colleagues point out that most serodiscordant couples do not engage in UAI.

The researchers came to this conclusion after analyzing data on 119 men in an HIV serodiscordant regular relationship of at least 6 months' duration.

Of these subjects, 82 reported no UAI and the remaining 37 reported "some." In those in whom the viral load was reportedly undetectable, the proportion engaging in UAI was 39.4%. In others, it was 20.8%.

As well as undetectable viral load, other significant predictors of UAI were being younger and having reduced concern about HIV and greater confidence in treatment being able to lessen HIV infectivity.

Although highly active antiretroviral therapy appears to diminish individual chances of transmission, the researchers conclude that "as more people are living with HIV and continue to have unprotected sex with both regular and casual partners, incident infection at a population level is likely to increase."

In fact, Dr. Mao told Reuters Health, "Gay men often acknowledge the importance of clinical markers -- such as HIV and viral load testings -- and incorporate such knowledge into day-to-day sexual risk reduction." However, it's important that "they be made aware that fluctuation of viral load in blood and in semen as well as variability of HIV strains further complicate HIV transmission."

In an accompanying editorial, Drs. Jonathan Elford and Graham Hart of City University London suggest that "interventions should target HIV-positive people to discourage further transmission of HIV and to reduce the likelihood of exposure to resistant virus."

02/25/05

AIDS 2005;19:179-184,205-207.