A recent post on the Center for Disease Control's website states that about every 1 in every 5 urban sexually active MSM (men who have sex with men) are infected with HIV. The report came apropos to the third annual National Gay Men's HIV/AIDS Awareness Day, observed on the 27th of September.

The report, which investigated over 8000 men in 21 major cities, estimates that of all the new HIV infections nearly 53% are from MSM individuals, about half of which had not even known they were infected.

Existent high prevalence of HIV in community, lack of knowledge of HIV status, attitudes toward the risk, social discrimination, substance abuse, and the internet are said to all be contributing factors to the increase risk and exposure for MSM.

Image source: CDC MSM FastFact Sheet

A quick overview of the report can be found here and the full report can be found here.