Methods We performed a retrospective cohort study of individuals with any interaction with the justice system (N = 259,867 individuals), including arrest, gaol, juvenile detention, juvenile prison, or adult prison, between 2000–2008 (gaol: 2003–2008). These individuals were linked to STI positive test result data (N = 82,990 individuals) using a probabilistic identity matching algorithm based on name, date of birth, and social security number. We identified individuals with chlamydia (CT), gonorrhoea (GC), syphilis, or incident HIV within 365 days of release (or of arrest date). We calculated annual STI incidence by justice system category, year, and demographic characteristics, and compared these to population rates within the same geographic area.

Results In cross-sectional analyses, 19% of individuals with any interaction with adult prison, 14% with gaol, 14% with arrest, 34% with juvenile prison, and 25% with juvenile detention had a positive STI. Average annual incidence of any STI in the year after release was 10% for adult prison, 13% for gaol, 10% for arrest, 26% for juvenile prison, and 22% for juvenile detention. These differences in incidence were driven by differing demographic compositions, with younger, minority and female populations demonstrating the highest rates of STI following release. Approximately 16% of all STIs (13% CT, 20% GC, 12% syphilis, 14% incident HIV) can be attributed to individuals within one year of release from the justice system.

Conclusions The time following any interaction with the justice system represents a high-impact opportunity to reduce STI burden at a population-level. Structural interventions targeting this vulnerable time period are indicated.