Syphilis testing and treatment outcomes among people experiencing homelessness: a street medicine intervention in South Los Angeles, California.

Abstract

OBJECTIVE: To evaluate the outcomes of a street medicine intervention offering syphilis testing and treatment to people experiencing homelessness in South Los Angeles, California-a population disproportionately affected by syphilis and underserved by traditional healthcare systems. METHODS: From September 2024 to January 2025, a multidisciplinary street medicine team provided testing and treatment for syphilis during outreach visits to patients experiencing homelessness. A total of 99 patients were tested using the reverse syphilis testing algorithm. Demographic data included gender, race/ethnicity, substance use disorder, mental illness and HIV status. χ2 tests were used to evaluate associations between syphilis diagnosis and each demographic characteristic. RESULTS: Thirty-six (36.4%) of the 99 patients had reactive syphilis test results, with 94.4% (n=34) classified as late-stage infections. Of those diagnosed, 72.2% (n=26) were treated during follow-up visits. Statistically significant associations were found between syphilis diagnosis and gender (p=0.002), substance use disorder (p=0.008) and HIV status (p=0.020). Patients identifying as female or transgender female, and those with cooccurring substance use disorder or HIV, were more likely to be diagnosed with syphilis. CONCLUSIONS: This study demonstrates the feasibility and outcomes of delivering sexually transmitted infection care through street medicine. The high prevalence of late-stage syphilis and its syndemic overlap with substance use disorder and HIV underscores the need for low-barrier, community-based services. Street medicine interventions should be recognised and resourced as essential tools in public health responses to rising syphilis rates, particularly among unhoused populations.