More MSM Practicing Sero-Sorting to Prevent HIV; MSM in Committed Relationships Less Likely to Practice Risky Behaviors, Studies Say

An increasing number of men who have sex with men in San Francisco are practicing sero-sorting -- in which people who know their HIV status search for partners of the same status -- as a way to protect against HIV, according to a study published Friday in the American Journal of Public Health, the San Francisco Chronicle reports. According to the Chronicle, sero-sorting evolved among MSM "without the kind of institutional support given to programs" that promote condom use and a reduction in sexual partners. The study authors, Dennis Osmond and colleagues at the University of California-San Francisco, found that 27% of MSM in San Francisco reported practicing sero-sorting in 2002, up from 19% in 1997. Forty percent of study participants ages 18 to 29 reported sero-sorting in 2002, the study found. The researchers also found that higher-risk sexual behaviors have increased among MSM, with the highest risk concentrated among men ages 30 to 50. Researchers found that the percentage of men reporting unprotected anal intercourse with a partner of different or unknown HIV status increased from 9% in 1997 to nearly 15% in 2002. The study also found that 27% percent of MSM in San Francisco were HIV-positive in 2002, compared with 20% in 1997. According to the Chronicle, the increase in HIV prevalence among MSM is "not surprising" because the study was conducted during a period when new antiretroviral drugs became available, which helped to "dramatically" reduce HIV/AIDS-related deaths.

In a second study, Sandra Schwarcz and colleagues at the San Francisco Department of Public Health also found that about 25% of MSM in the city are HIV-positive, the Chronicle reports. Schwarcz also found that MSM in committed relationships are less likely to practice risky sexual behaviors with each other than partners in more casual relationships. Mitch Katz, director of the health department and a study co-author, said the study shows a deviation in behavior from the early days of the HIV/AIDS epidemic, when the risk of transmission was highest among MSM in committed relationships. "The higher risks occurred with the more intimate relationships," he said, adding, "People took their highest risk with their closest partner." Both studies were conducted by telephone surveys among thousands of randomly selected men (Russell, San Francisco Chronicle, 4/27).

The American Journal of Public Health study is available online.

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