By Liz Highleyman

In recent years, public health experts have increasingly recognized the value of effective antiretroviral therapy as a means of preventing HIV infection, since people with low or undetectable HIV viral loads are less likely to transmit the virus. Intermittent antiretroviral therapy, which can lead to periodic increases in viral load, may thus increase the likelihood of HIV transmission.

At the 14th Conference on Retroviruses and Opportunistic Infections last week in Los Angeles, researchers presented a poster on HIV transmission risk behavior in the CPCRA SMART Study, which compared the safety and efficacy of 2 treatment strategies: CD4-guided intermittent therapy and continuous therapy.

The study was terminated in January 2006 after an interim analysis showed that patients in the intermittent therapy arm were more likely to experience disease progression or death. Results were published in the November 30, 2006 New England Journal of Medicine.

The transmission risk sub-study included 883 participants. At baseline and throughout the study, they completed written surveys about their sexual activity and needle-sharing behavior, and were tested for sexually transmitted infections.

At the start of the study, about 15% reported recent sexual or needle-sharing risk behavior or had a sexually transmitted infection, indicating ongoing sexual risk. During follow-up, self-reported risk behavior and sexually transmitted infection rates were similar in the intermittent therapy and continuous therapy arms.

The researchers concluded, "Because HIV RNA levels were higher overall among patients on episodic therapy, this strategy may result in increased HIV transmission to partners."

Denver Public Health, CO; University of Minnesota, Minneapolis, MN; CDC, Atlanta, GA; Yale University School of Medicine, New Haven, CT.

Link to study abstract.

03/06/07

References

W Burman, B Grund, J Neuhaus, and others. The Effect of Episodic ART on HIV Transmission Risk: A Substudy of the SMART Study. 14th Conference on Retroviruses and Opportunistic Infections. Los Angeles. February 25-28, 2007. Abstract 979 (poster).

W M El-Sadr, J D Lundgren, J Neaton, and other (the SMART Study Group). CD4+ Count-Guided Interruption of Antiretroviral Treatment. New England J Medicine 355(22): 2283-2296. November 30, 2006.