AIDS 2014Comparatively higher HIV testing frequency and higher rates of safer sex among San Francisco men who have sex with men (MSM) may account for the city’s lower rate of undiagnosed MSM and lower HIV diagnosis rate when compared with London MSM, aidsmap reports. Researchers analyzed surveillance and behavioral data on MSM in the two cities and presented their findings at the 20th International AIDS Conference (AIDS 2014) in Melbourne, Australia.

Out of 234,000 MSM in London, an estimated 8.7 percent are HIV positive, compared with 24 percent of San Francisco’s 64,000 MSM. Since 2006, the annual HIV diagnosis rate in London has risen from 563 to 696 per 100,000 MSM, while the proportion of MSM living with the virus but unaware of their serostatus remained steady at about 20 to 25 percent. Among San Francisco MSM, the annual HIV diagnosis rate fell from 694 to 442 during that time, and the proportion of undiagnosed MSM living with HIV dropped from 21.7 percent to 7.5 percent.

While HIV testing rates among MSM increased in both cities, in 2011 London MSM tested less frequently than those living in San Francisco, with a respective 16.9 percent and 34.4 percent of the HIV-negative MSM testing in each city during that year. In 2010, London had higher rates of newly diagnosed MSM linking into care within three months (94.5 percent versus 82.9 percent, when compared with San Francisco), retention in care (96 percent versus 76.9 percent) and viral suppression among MSM with HIV (81.7 percent versus 65.1 percent).

The rate of serodiscordant condomless anal intercourse among MSM has fallen in London, but in 2008 the rate was higher at 17.6 percent among HIV-negative MSM, when compared with 9.8 percent in San Francisco.

To read the conference abstract, click here.

To read the aidsmap story, click here.