# HIV, STI, and Hepatitis Among People Who Inject Drugs at a Sexual Health Clinic in Melbourne, Australia: 2012 to 2022

## TL;DR

This study analyzed STI and HIV rates among drug injectors in Melbourne from 2012 to 2022, finding rising syphilis rates and high infection risks.

## Contribution

The study provides updated data on STI and blood-borne virus prevalence among PWID in Australia over a decade.

## Key findings

- Syphilis positivity increased significantly from 0.6% in 2012/2013 to 10.0% in 2020/2021.
- gbMSM had higher infection positivity (29.1%) compared to other groups.
- HCV antibody positivity was 10.0%, but only 37.6% of clients were tested for HCV.

## Abstract

This study aimed to examine the sexual practices and sexually transmitted infection (STI) positivity among people who inject drugs (PWID).

This was a repeated cross-sectional study analyzing data collected at a sexual health center during 2012–2022. New clients who were aged 18 and older, sexually active, and had injected drugs in the last 12 months were eligible for inclusion. Clients were categorized as men who have sex with women only (MSWO), gay or bisexual men who have sex with men (gbMSM), or women. We calculated the 2-year positivity of HIV, STIs, hepatitis B virus (HBV), and hepatitis C virus (HCV), and temporal analyses were conducted using the chi-square trend test.

A total of 1229 clients (395 MSWO, 457 gbMSM, and 377 women) were included in the study. There was a significant rise in syphilis (Ptrend = .0033); however, no significant changes were observed for other infections. The 2-year positivity for syphilis increased significantly from 0.6% (1/156) in 2012/2013 to 10.0% (13/130) in 2020/2021 (Ptrend = .0033). gbMSM had higher positivity for any infection (29.1%, 133/457) than MSWO (19.8%, 78/395) and women (17.0%, 64/377; P < .001). Positivity of new HIV was 2.6% (95% CI, 1.6%–3.8%; 22/861), infectious syphilis was 6.8% (95% CI, 5.2%–8.7%; 59/866), gonorrhea was 8.6% (95% CI, 6.8%–10.7%; 77/892), chlamydia was 8.7% (95% CI, 7.0%–10.5%; 95/1093), HBV was 0.6% (95% CI, 0.1%–1.6%; 3/545), and HCV antibody was 10.0% (95% CI, 7.4%–13.2%; 45/448). The HCV testing rate was 37.6% (462/1229).

PWID are highly susceptible to STIs and blood-borne infections. Future prevention programs directed at PWID must include increasing the rate of HCV testing and messages related to sexual risk practices to help reduce the burden of disease in PWID.