Mackrell Lucy, Antoun Jillian P, Carter Megan, Larkin Natasha, Burnside Jessica, Hoover Maggie, Khandakar Farhan, O'Byrne Patrick, Cassan Casey, Burbidge Jennifer, Vance Stephanie, Belanger Kandace, Saeed Sahar
Queen's University, Kingston, Canada.
South East Health Unit (formerly Kingston, Frontenac and Lennox & Addington Public Health), Kingston, Canada.
Open Forum Infect Dis. 2025 Aug 7;12(8):ofaf472. doi: 10.1093/ofid/ofaf472. eCollection 2025 Aug.
Syphilis has reemerged as a global public health concern. In Ontario, Canada's most populous province, a 340% increase in infectious syphilis cases was observed between 2013 and 2023. This surge was accompanied by a demographic shift, with women emerging as the fastest-growing at-risk group. We examined intersecting risk factors associated with syphilis seropositivity among a street-involved population.
Data were collected from the Syphilis Point of Care Rapid Test and Immediate Treatment Evaluation (SPRITE) study-an outreach model of care implemented by 8 public health units (PHUs) across Ontario between 2023 and 2024. Reactive treponemal antibodies defined syphilis seroprevalence. A mixed-effects regression with a log-binomial distribution was used to evaluate the association between risk factors and seropositivity. Adjusted prevalence ratio (aPR) controlled for age and sex and clustering by PHUs.
A total of 630 participants, 42% women, with a median age of 38, were included; 19.1% of participants reported having sexual risk factors, using illicit drugs, and being un(der)housed. Overall, syphilis seroprevalence was 7.6% (95% confidence interval 5.5-9.7), with significant heterogeneity across the province and higher among those reporting 3 risk factors (19.2% [11.2-29.7]) compared with 1 risk factor (4.8% [1.8-10.1]). Seropositivity was higher among women (aPR 1.62 [.94-2.80]) and people who use illicit drugs (aPR 2.30 [.93-5.50]), particularly those who use crystal methamphetamine (aPR 2.88 [1.31-6.33]).
Syphilis is heightened at the intersection of sexual risk factors, illicit drug use, and housing instability among equity-deserving populations. Targeted outreach models of care are necessary to reach this emerging at-risk population.
梅毒已再度成为全球公共卫生关注的问题。在加拿大人口最多的安大略省，2013年至2023年间，感染性梅毒病例增加了340%。这种激增伴随着人口结构的变化，女性成为增长最快的高危群体。我们研究了街头涉险人群中与梅毒血清阳性相关的交叉风险因素。
数据来自梅毒即时护理快速检测与即时治疗评估（SPRITE）研究，这是安大略省8个公共卫生单位在2023年至2024年实施的一种外展护理模式。反应性梅毒螺旋体抗体定义梅毒血清阳性率。采用对数二项分布的混合效应回归来评估风险因素与血清阳性之间的关联。调整后的患病率比值（aPR）对年龄、性别以及公共卫生单位的聚类进行了控制。
共纳入630名参与者，其中42%为女性，中位年龄为38岁；19.1%的参与者报告有性风险因素、使用非法药物以及无家可归（或住房不足）。总体而言，梅毒血清阳性率为7.6%（95%置信区间5.5 - 9.7），全省存在显著异质性，报告有3个风险因素的人群（19.2% [11.2 - 29.7]）高于报告有1个风险因素的人群（4.8% [1.8 - 10.1]）。女性（aPR 1.62 [.94 - 2.80]）和使用非法药物的人群（aPR 2.30 [.93 - 5.50]）血清阳性率更高，尤其是使用冰毒的人群（aPR 2.88 [1.31 - 6.33]）。
在应受关注人群中，梅毒在性风险因素、非法药物使用和住房不稳定的交叉点上更为突出。有针对性的外展护理模式对于接触这一新兴高危人群是必要的。
