The number and proportion of HIV infections among men who have sex with men (MSM) in New York City are still increasing, according to a report released World AIDS Day, December 1, by the New York City Department of Health and Mental Hygiene.

According to preliminary numbers—data from 2008 are not yet final—the number of overall new HIV diagnoses in New York City is close to the 2007 total of 3,965. However, MSM accounted for 42 percent of the city's new HIV diagnoses, up from 37 percent four years earlier.

Officials estimate that the rising proportion reflects a sharp increase in actual infections among MSM ages 13 to 29. In that group, new HIV cases rose from 551 in 2004 to 706 in the 2008 partial count.

For the investigation, researchers invited 550 MSM ages 18 to 29 to popular venues to get tested and talk about their sexual behaviors. Twenty-nine percent of volunteers tested positive for HIV.

Nearly one in five of study participants reported unprotected anal sex with one or more male partners during the past year, and 10 percent had intercourse with a male partner who was positive or didn't know his status.

The health department funded another study at New York University, which had similar results. In this instance, researchers found that minority MSM such as black men (12 percent) and Hispanic men (9 percent) are more likely to disclose their status than white men (2 percent). Those who reported being HIV positive also had more sexual partners in the past three months than HIV-negative men. Of the 339 men who reported a casual sexual partner in the past three months, 19 percent said their most recent encounter included unprotected anal sex.

“Every day should be World AIDS Day, as the epidemic is far from over,” said Monica Sweeney, MD, the health department's assistant commissioner for HIV/AIDS Prevention and Control. “MSM and others at risk need to use condoms consistently and choose fewer partners when they're not in monogamous relationships.”