26 August 2025
At the STI and HIV World Congress in Montreal, INHSU co-hosted a symposium on bacterial sexually transmissible infections (STIs) among people who use drugs and those in prison, led by Brendan Harney (co-chair of INHSU EMCR Special Interest Group) and Nadine Kronfli (McGill University).
In countries like Australia, Canada, and the United States, bacterial STIs, especially syphilis, are on the rise. Yet, compared with viral infections such as hepatitis C and HIV, bacterial STIs receive little attention among these two key populations, including at most major conferences. This symposium aimed to redress that imbalance.
Here, Brendan shares his key takeaways from the event:
Syphilis Among People Who Inject Drugs
Dr. Olivia Price (University of New South Wales) opened with findings from her systematic review of bacterial STIs among people who inject drugs. Prevalence of active syphilis was 3.2%—six times higher than the general population. Prevalence of chlamydia and gonorrhoea varied widely, though the evidence base was limited and often outdated. Dr. Price called for more robust data collection, recommending that “existing bio-behavioural surveys should consider including syphilis testing.”
STIs in Carceral Settings
Next, Dr. Gabrielle Beaudry (McGill University) presented her review of bacterial STIs among people who are incarcerated. She reported:
- Higher prevalence among women than men
- Adolescents most affected: chlamydia prevalence was 16.9% among adolescent women vs 6.9% among adults; gonorrhoea prevalence was 6% vs 1.4%
- Syphilis patterns differed: higher among adult men (4.7%) and women (6.5%) compared to adolescents (1.9%).
These results highlight the urgent need for STI testing and treatment in correctional facilities, alongside accessible, stigma-free sexual health services in the community.
Harm Reduction and Person-Centered Care at Florida’s first legal Needle & Syringe Exchange
Dr. Edward Suarez presented findings from the IDEA Exchange—the first legal syringe exchange in Florida. Among women participating in the Women’s Engagement Initiative:
- 91 women, approximately a third had a history of syphilis infection
- There is a need to go beyond urine testing as, while 7.7% and 14.3% tested positive for chlamydia and gonorrhoea respectively based on urine testing, 3.3% and 9.9% also had positive oropharyngeal tests
- Rectal STIs were the most common, with 13.2% and 16.5% testing positive for chlamydia and gonorrhoea
All women received treatment, demonstrating how harm reduction services can deliver holistic, person-centered care that addresses both health and social needs.
Nurse-Led Models Expanding to Syphilis Care
Tamara Barnett (CoolAid Community Health Centre) showcased how nurse-led hepatitis C care in prisons and community settings has successfully expanded to include syphilis testing and treatment. Between 2021 and 2024:
- 269 people tested positive for syphilis exposure
- 111 had current infections
- 42% of current infections were among females, and 24% were among males who did not identify as gay or bisexual
- More than 95% across all groups were successfully treated
As Barnett emphasized: “Syphilis cannot be ignored. The communities we work with trust us and we have a responsibility to meet their needs.”
Tackling Syphilis in Alberta’s Prisons with point-of-care testing
Finally, Jennifer Gratrix (Alberta Primary Care) highlighted the growing burden of syphilis in correctional facilities. In 2022, nearly one in five infectious syphilis notifications in Alberta came from these settings. Testing strategies made a clear difference:
- Opt-in testing: 0.3% new infections detected
- Opt-out testing: 7.3%
- Point-of-care testing: 17%
This demonstrates the critical role of testing strategies in identifying infections and preventing transmission.
Final thoughts
As demonstrated by these presentations, people who use drugs and people who are incarcerated are at increased risk of STIs. Encouragingly, existing models of care and programs can offer STI testing with the vast majority of people being successfully treated. While there are still many gaps in our understanding of bacterial STIs among these populations, given the clear shifting epidemiology of syphilis in particular, a proactive approach to addressing this may help avert what could easily become another major health issue if it continues to be neglected.
