Heroin type, injecting behavior, and HIV transmission. A simulation model of HIV incidence and prevalence

Abstract

Background and aimsUsing mathematical modeling to illustrate and predict how different heroin source-forms: “black tar” (BTH) and powder heroin (PH) can affect HIV transmission in the context of contrasting injecting practices. By quantifying HIV risk by these two heroin source-types we show how each affects the incidence and prevalence of HIV over time. From 1997 to 2010 PH reaching the United States was manufactured overwhelmingly by Colombian suppliers and distributed in the eastern states of the United States. Recently Mexican cartels that supply the western U.S. states have started to produce PH too, replacing Colombian distribution to the east. This raises the possibility that BTH in the western U.S. may be replaced by PH in the future.DesignWe used an agent-based model to evaluate the impact of use of different heroin formulations in high- and low-risk populations of persons who inject drugs (PWID) who use different types of syringes (high vs. low dead space) and injecting practices. We obtained model parameters from peer-reviewed publications and ethnographic research.ResultsHeating of BTH, additional syringe rinsing, and subcutaneous injection can substantially decrease the risk of HIV transmission. Simulation analysis shows that HIV transmission risk may be strongly affected by the type of heroin used. We reproduced historic differences in HIV prevalence and incidence. The protective effect of BTH is much stronger in high-risk compared with low-risk populations. Simulation of future outbreaks show that when PH replaces BTH we expect a long-term overall increase in HIV prevalence. In a population of PWID with mixed low- and high-risk clusters we find that local HIV outbreaks can occur even when the overall prevalence and incidence are low. The results are dependent on evidence-supported assumptions.ConclusionsThe results support harm-reduction measures focused on a reduction in syringe sharing and promoting protective measures of syringe rinsing and drug solution heating.

Growing racial/ethnic disparities in overdose mortality before and during the COVID-19 pandemic in California

“…While fatal overdose represents a “worst possible” outcome of substance use, these overdose trends foreshadow impacts on morbidity that could occur years into the future. For example, the replacement of black tar heroin with fentanyl has been associated with increased risks for HCV and HIV infection, due to increased injection frequency and differences in drug preparation ( Lambdin et al, 2019 ; Bobashev et al, 2019 ). Additionally, non-fatal overdoses are associated with substantial morbidity and increased risk of mortality ( Warner-Smith et al, 2002 ; Weiner et al, 2020 ).…”

Modeling HIV transmission among persons who inject drugs (PWID) at the “End of the HIV Epidemic” and during the COVID-19 pandemic

“…urban or rural) when more information about specific structures is known. In model development, we leveraged our past experience with ABMs that simulated HIV transmission among PWID (though none of these prior studies was specific to HIV among PWID in New York City) (Zule (2009, 2018)( Zule and Bobashev, 2009 ; Zule et al, 2018 ) and Bobashev et al (2010, 2019) ( Bobashev et al, 2019 ; Bobashev and Zule, 2010 )).…”

“…Outbreak in Scott County, IN in 2014) ( Broz et al, 2018 ). We follow Zule et al (2009, 2018) ( Zule and Bobashev, 2009 , Zule et al, 2018 ) and Bobashev et al (2010, 2019) ( Bobashev et al, 2019 , Bobashev and Zule, 2010 ) and consider estimates of HIV transmission per shared injection after an HIV-infected not on ART person being p = 0.00008. Sexual transmission: Following a CDC report (Centers for Disease Control & Prevention, 2017) we consider sexual HIV incidence among PWID to be 2 per 10,000 person years.…”

“…Outbreak in Scott County, IN in 2014) ( Broz et al, 2018 ). We follow Zule et al (2009, 2018) ( Zule and Bobashev, 2009 , Zule et al, 2018 ) and Bobashev et al (2010, 2019) ( Bobashev et al, 2019 , Bobashev and Zule, 2010 ) and consider estimates of HIV transmission per shared injection after an HIV-infected not on ART person being p = 0.00008.…”

Methodological approaches for the prediction of opioid use-related epidemics in the United States: a narrative review and cross-disciplinary call to action

“…Bobashev et al employed an agentbased modeling approach to explore the impact of different types of heroin (powder vs black tar), different types of needles (high vs low dead space), and various injection practices (such as syringe sharing) on HIV incidence. 78 This approach highlights both the feasibility and necessity of incorporating variations in drug type (driven by drug market availability) and route of administration when attempting to predict OREs. In a more experimental fashion, substance use has been modeled as a communicable behavior.…”