Evaluating the Impact of Implementing and Scaling-Up the Use of Syphilis Rapid/Point-of-Care Tests (RPOCTs): An Interrupted Time Series Analysis of New Syphilis Positivity Rates in Alberta, Canada.

Abstract

In July 2019, a syphilis outbreak was declared in Alberta, Canada, affecting key populations. Syphilis rapid/point-of-care testing (RPOCT) provides opportunities to test individuals in nontraditional settings and provide same-day treatment. This study aimed to evaluate whether RPOCT resulted in a decline in new syphilis positivity rates. Starting August 2020, syphilis RPOCTs were implemented in a single (Edmonton) health zone (EDM phase) and in March 2022 were scaled up across the province of Alberta (ProvScaleUp phase). To evaluate the impact of RPOCTs on new syphilis positivity rates, interrupted time-series analyses were used to analyze population-standardized new syphilis positivity rates before, during, and after RPOCT implementation. Generalized linear models assessed percentage declines in new syphilis positivity rates after RPOCT implementation. In the preintervention period, monthly new syphilis positivity rates significantly increased across Alberta. After RPOCTs were implemented regionally (EDM phase), syphilis positivity rates decreased by an average of 15% (0.25 per 100 000 population). After wider distribution (ProvScaleUp phase), provincial rates decreased by 25% (0.22 per 100 000 population). Rates decreased more in the general versus prenatal population (15.9% vs 12.2%), among males versus females (16.0% vs 14.5%), among those in metropolitan versus urban and rural areas (15.2%, 14.0%, and 12.2%, respectively) and decreased the least among those aged 24-29 (12.5%). Syphilis RPOCT implementation was associated with a significant decrease in new syphilis positivity rates in a province of a high-income country experiencing a resurgence of heterosexual syphilis among key populations facing barriers to testing and treatment.