Hepatitis C is a more widespread health problem than HIV among the prison population, according to a report published by the Irish Prisons Service.
It shows that of 607 prisoners admitted to custody in the State in April and May of last year, 22 per cent had antibodies for hepatitis C.
Just over 6 per cent had antibodies for hepatitis B and only 2 per cent had antibodies for HIV.
The survey was conducted by the department of community health and general practice at Trinity College Dublin.
Nearly one in three (31 per cent) of the prisoners in the survey reported smoking heroin in the previous year and 29 per cent said they had injected drugs at some stage.
Seventeen per cent of those who injected heroin said they first injected while in prison.
But the press release from the Irish Prisons Authority outlining the survey's results casts some doubt on the reliability of this claim.
"Prison management is, however, generally sceptical of these particular figures it must be said, given the deprived social background of most of the prisoners concerned and the known propensity of prisoners to blame their health troubles on the authorities rather than themselves," it says.
Levels of infection and serious drug misuse were generally higher in female prisoners than in men. Two-thirds (65 per cent) of females reported smoking heroin in the previous year compared with 28.2 per cent of men, and almost the same proportion (60.5 per cent) reported injecting drugs compared with 26.6 per cent of men.
They were three times more likely to test positive for Hepatitis B, seven times more likely to test positive for Hepatitis C and almost 10 times more likely to test positive for HIV.
"Clearly women prisoners have particularly acute healthcare needs in the area of drug counselling and medical treatment for drug-related illnesses and infections," the report says.