Study offers new insight on HIV transmission risk of men who have sex with men

August 7, 2008

Approximately half of all new HIV infections in the United States result from the sexual risk behaviors of men who have sex with men. Now, a new study led by a researcher at The Miriam Hospital provides additional insight into which of these men are most likely to transmit HIV to others, potentially paving the way for the development of more targeted prevention programs.

Based on the study's findings, which were presented today, August 7, at the XVII International AIDS Conference (AIDS 2008) in Mexico City, researchers suggest that prevention programs for HIV-infected men who have sex with men focus on younger, more recently diagnosed men, as well as those who binge drink and use substances such as methamphetamine.

"Although the number of HIV diagnoses among men in this group decreased the last two decades, recent data shows these rates are on the rise again, making it critical that we continue to understand this group in order to guide prevention and education efforts," says lead author Kenneth H. Mayer, MD, an infectious disease physician at The Miriam Hospital and a professor of medicine at The Warren Alpert Medical School of Brown University.

Approximately 200 HIV-infected men who have sex with men participated in an HIV transmission risk reduction behavioral intervention. They completed a computer-administered psychosocial assessment that showed just about half of the men had a detectable amount of virus in their blood, known as an HIV viral load, and 57 percent were on highly active antiretroviral therapy (HAART), a combination of antiretroviral drugs aimed at treating HIV. Three-quarters of the men were Caucasian and more than half were college-educated.

Based on data analysis, researchers determined that about half of the participants in the study met the criteria for being a high-risk HIV transmitter. This was defined as engaging in unprotected insertive or receptive anal intercourse over the last six months with partners who are either HIV positive or of unknown status. It also includes men who have a detectable HIV viral load or have been diagnosed with a sexually transmitted infection (STI) within the past year.

Nearly a quarter of men surveyed said they consumed five or more alcoholic drinks daily at least once in the previous three months and 65 percent reported other substance use, including 30 percent who admitted to using methamphetamine. Within the past year, about 12 percent of men were diagnosed with an STI.

"When one drinks or uses other substances, inhibitions are lowered, making people more likely to engage in risky behavior, like unprotected sex. This is particularly true for young people, who often take risks without thinking about the consequences. Some patients who are newly diagnosed might be in denial, which could lead to poor decisions when it comes to sex," Mayer says. "Unfortunately, such behaviors put the partners of these men at great risk for contracting HIV and unknowingly transmitting it to others."

Source: Lifespan