Trends in sexually transmitted infection diagnoses among people in prison in England, 2018-2023: analysis of surveillance and pilot seroprevalence data.

Purpose: People in prison face a disproportionate risk of sexually transmitted infections (STIs), but there is a paucity of evidence on trends in STIs in prisons in England. This study aims to describe trends in chlamydia test-positivity and syphilis prevalence by using two different methodologies in prison settings.

Design/methodology/approach: This study used routinely collected chlamydia surveillance data reported by all primary diagnostic laboratories in England from 2018 to 2022 to identify tests undertaken in prisons. Separately, this study used data from a pilot syphilis serology pilot study of four prisons in England. A descriptive analysis was undertaken to describe chlamydia test-positivity and syphilis seroprevalence by demographic characteristics.

Findings: Between 2018 and 2022, the number of chlamydia tests carried out in prisons increased by 2.0% (17,177-17,514) whilst the number of positive diagnoses decreased by 12.0% (957-840). The overall test-positivity in 2022 was 4.8% (840/17,514) which was marginally lower than that of the community; test-positivity was highest in 15-19 year-olds. Overall, syphilis prevalence was 3.9% (43/1064). Prevalence was highest in the women's prison site at 6.4% 27/398). The range in male prison sites was between 0.5% and 3.5%.

Originality/value: Use of two methods enabled us to better understand the burden of STIs in a vulnerable population. Chlamydia test positivity was marginally lower than community levels but still indicated a high burden of infection, in particular for the 15-24 age group. Syphilis prevalence was high across all age groups in prisons, highlighting the need for more systematic assessment of STIs in prisons to allow for earlier identification and treatment of infections.