Chlamydia and gonorrhoea testing and positivity among women prescribed opioid agonist therapy in Australia

BACKGROUND: Women who inject drugs have complex sexual risk profiles, but STI epidemiology in this population is not well understood. We sought to describe chlamydia and gonorrhoea testing and positivity among women with a history of opioid agonist therapy prescriptions, as a proxy for a history of injecting drug use. METHODS: We extracted de-identified linked data from individuals with sex recorded as female aged 15-55 years attending clinics within the Australian Collaboration for Coordinated Enhanced Sentinel Surveillance of Sexually Transmissible Infections and Blood-borne Viruses national sentinel surveillance network between 1 January 2012 and 31 December 2025. We describe overall test uptake and annual test positivity for chlamydia and gonorrhoea using a linear test of trend, reported as a P-value. We report by a binary age grouping of <30 and ≥30 years of age. RESULTS: Of 6850 women prescribed opioid agonist therapy, 2303 (34%) had a test for chlamydia or gonorrhoea. Chlamydia overall test positivity was 4%; 7% in women aged <30 years and 3% in women aged ≥30 years. In women aged <30 years, annual chlamydia test positivity increased from 6% in 2012 to 12% in 2023 (P = 0.158). For gonorrhoea, overall test positivity was 3%; 4% in women aged <30 years and 2% in women aged ≥30 years. In women aged <30 years, gonorrhoea test positivity increased from 0% in 2012 to 14% in 2020 (P < 0.001). CONCLUSIONS: We found high test positivity for chlamydia and gonorrhoea among women with a history of opioid agonist therapy, indicating the sexual health needs of this population are not being met. Increasing chlamydia and gonorrhoea positivity, particularly among young women, highlights the need for more research into the epidemiology of STIs among women who inject drugs.