Exploring Sexually Transmitted and Bloodborne Infection Rates in Florida After Implementation of Syringe Services Programs: A Quasi-Experimental Study.

Introduction: The aim of this study was to evaluate the associations between syringe services program implementation and sexually transmitted and blood-borne infection rates in Florida counties. Methods: A difference-in-difference analysis was conducted using surveillance data (2010-2023) to compare sexually transmitted and blood-borne infection rates, including nonviral sexually transmitted infections (i.e., chlamydia, gonorrhea, infectious syphilis), acute hepatitis C virus, and HIV, before and after syringe services program implementation in Florida counties with operational syringe services programs versus control counties without syringe services programs. Two-way fixed-effects models were used to estimate average treatment effects, and multiple sensitivity analyses explored the robustness of the results. Results: Syringe services program implementation was associated with significant reductions in HIV rates (-11 per 100,000; 95% CI= -15.4, -6.7 in Miami-Dade County vs control counties), and hepatitis C virus rates appeared stable, whereas nonviral sexually transmitted infection rates appeared to increase. Conclusions: Syringe services programs appear to be effective in reducing HIV at the population level in Florida. The observed increase in sexually transmitted infection rates may reflect improved detection facilitated by syringe services programs and linkage to other care. Findings support the expansion of syringe services programs as a public health strategy and highlight the need for research on their broader population-level impact.