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ID: HR19-682

Presenting author: William Goedel

Presenting author biography:

Mr. Goedel is a graduate of the New York University College of Global Public Health. He is a doctoral student in the Department of Epidemiology at the Brown University School of Public Health in Providence, Rhode Island.

Can emergency implementation of syringe services programs prevent rapid HIV transmission among people who inject drugs in rural counties in the United States?: A modeling study

William Goedel, Maximilian King, Mark Lurie, Sandro Galea, Jeffrey Townsend, Alison Galvani, Brandon Marshall

Background: Syringe services programs (SSPs) often face barriers to implementation in rural areas of the United States, including resource limitations and stigma. These challenges are exacerbated when the risks of HIV transmission are perceived to be low. During recent outbreaks among people who inject drugs (PWID), emergency implementation of an SSP represented the only opportunity to bring essential harm reduction services, including syringe exchange, into these communities.

Methods: Using an agent-based model, we simulated HIV transmission in a rural county in the United State and compared HIV incidence among PWID arising in the absence of an SSP, in the presence of a pre-existing SSP, and with reactive implementation of an SSP (i.e., after ten new HIV diagnoses) over five years following the introduction of a single infection into the injection network. Model parameters were largely derived from data collected during a recent injected-related HIV outbreak in Scott County, Indiana.

Results: In the absence of an SSP, the model predicted 137 infections (IQR: 78–171) among PWID over five years or an incidence rate of 6.6 per 100 person-years (IQR: 3.9–8.4). Proactive SSP implementation averted 109 infections (IQR: 62–141) and decreased incidence by 80.1% (IQR: 69.9%–88.7%). Under reactive implementation, an SSP would, on average, begin operating ten months after the first infection, averting 78 infections (IQR: 40–107) and decreasing incidence by 56.3% (IQR: 44.1%–65.9%).

Conclusion: Reactive SSP implementation is effective in reducing the eventual size of HIV outbreaks among PWID in rural counties in the United States similar to Scott County, Indiana. However, proactive SSP implementation is more effective. Furthermore, the impact of reactive SSP implementation is highly dependent on the timely detection of the earliest infections. Consequently, there is a need for expanded proactive SSP implementation in the context of enhanced monitoring of outbreak vulnerability in these areas.