Prevalence of Mantoux positivity and annual risk of infection for tuberculosis in New South Wales prisoners, 1996 and 2001.

OBJECTIVES This study compares the prevalence of Mantoux positivity among prisoners in NSW in 1996 and 2001 and examines factors associated with Mycobacterium tuberculosis infection. DESIGN Cross-sectional random samples of prisoners, including a longitudinal cohort of prisoners screened in both 1996 and 2001. SETTING 29 correctional centres. PARTICIPANTS 747 men and 167 women participated in the 2001 NSW Inmate Health Survey; a cohort of 104 prisoners from the 1996 and 2001 NSW Inmate Health Surveys. RESULTS The prevalence of Mantoux positivity remained stable between 1996 and 2001 (12% and 14%, p = 0.2), and increased among prisoners from Asian backgrounds (21% and 47%, p = 0.02). The annual risk of infection in the cohort among those detained continuously between 1996 and 2001 was 3.1%, and among recidivists it was 2.7% (p = 0.6). CONCLUSION The risk of M. tuberculosis infection for Australian prisoners is assessed to be approximately four times higher than that for the community, however there is no attributable risk to the prison environment itself.