HIV Prevalence Among People In State Prisons

"The percentage of State prison inmates who were HIV positive was —

"1.3% of those who never used drugs
"1.7% of those who had ever used drugs
"1.9% of those who used drugs in the month before their current offense
"2.8% of those who had used a needle to inject drugs
"5.1% of those who had shared a needle.

"Like State inmates, Federal inmates who used a needle and shared a needle had higher rates of HIV infection than those inmates who reported ever using drugs or using drugs in the month before their current offense."

Source: 

Maruschak, Laura M. HIV In Prisons, 2004. NCJ-213897. Washington, DC: Department of Justice, Bureau of Justice Statistics, Nov. 2006.