1 in 5 Gay Men in Big Cities Have HIV

Nineteen percent of gay and bisexual men in major U.S. cities have HIV, but half of those infected are unaware they carry the virus, according to a government study.

Jonathan Mermin, director of the U.S. Centers for Disease Control and Prevention's HIV/AIDS Prevention division, said the proportion of those who did not know whether they were HIV-positive was high for black men.

The study tested 8,153 men in 21 of the nation's major cities for the 2008 National HIV Behavioral Surveillance System, according to Reuters. The results showed that 28% of black gay and bisexual men had the virus, while 18% of Latino men and 16% of white men were infected.