Patrick Letellier, PlanetOut Network, April 22, 2006.

Contrary to popular belief, men in prison with HIV are most likely to have acquired the virus before they were imprisoned, according to a federal study released Thursday by the U.S. Centers for Disease Control and Prevention (CDC).

Rates of HIV infection among inmates in America's prisons are four times higher than in the general population, the study says, but researchers found that 91 percent of HIV-positive men in Georgia prisons had already contracted HIV by the time of their incarceration.

The study examined HIV rates in Georgia's prison system, which is the nation's fifth largest and houses almost 50,000 inmates. Since 1988, Georgia has been testing inmates for HIV when they arrive in prison, and researchers found that between 1988 and 2005, 88 men who tested negative when they came into prison later seroconverted while in custody.

Researchers looking to find out more about how HIV transmission occurs behind bars interviewed 68 HIV-positive men currently serving time in Georgia prisons.

Patrick Sullivan, the CDC epidemiologist who led the study, told the PlanetOut Network that of the 48 men who reported having consensual sex in prison, only 30 percent used condoms or other makeshift barriers, like latex gloves or plastic wrap. The use of barriers dropped further (to 21 percent) among men who reported having "exchange sex," that is, sex in exchange for goods like cigarettes or candy, or in exchange for protection from violence. Of the seven men who reported being raped in prison, none reported the use of protection.

AIDS is the second-leading cause of death in U.S. prisons, and only Mississippi and Vermont allow inmates in state prisons access to condoms.

Besides low HIV transmission rates, the study revealed several other surprises, namely a low number of men (7) reporting sexual assaults, and a high number (37) reporting having consensual sex with corrections officials.

But prisoner rights experts contend that sex between inmates and corrections officials cannot be considered consensual.

"It's inherently coercive because the official has power over the inmate's life in ways that don't exist in the outside world," said Kathy Hall-Martinez, co-director of Stop Prisoner Rape, a national group working to prevent sexual assault behind bars.

Corrections officials control when an inmate eats, sleeps, and whether or not he can bathe or have time outside, Hall Martinez said. "They control everything about the inmate's daily life, so if an inmate refuses sex there's a great chance it will result in the lowering of the quality of his life," she said. "There is no such thing as consent in that situation."

Because HIV transmission and sexual assault in prison are such complex issues, Sullivan believes that education and prevention strategies are essential, especially given that 97 percent of inmates will eventually be released back into their communities.

"Prison is a hub where men come in, where men have risk exposures, and a hub where men go back out. And it's a place where you can intervene and teach prevention skills," he said.