Illicit Fentanyl Use Linked to Greater HCV Risk Among People Who Inject Drugs

Steffanie Strathdee, PhD

Credit: UC San Diego

New research has unveiled a significant association between illicit fentanyl use and hepatitis C virus (HCV) transmission among people who inject drugs (PWID).¹

The study followed a cohort of nearly 400 PWID over a span of 2 years and found use of illicitly manufactured fentanyl was linked to a 64% increased risk of acquiring HCV, highlighting a novel association between illicit fentanyl and HCV seroconversion in this patient population.¹

"Our study provides the first evidence that illicit fentanyl use is linked to an increased risk of acquiring hepatitis C infection, which disproportionately affects people who inject drugs," Steffanie Strathdee, PhD, senior author and professor of medicine at UC San Diego School of Medicine, said in a press release.² "This underscores the importance of making point-of-care HCV viral load testing more widely available in the US, so those needing treatment can access it immediately."

According to the World Health Organization (WHO), globally, an estimated 50 million people have chronic hepatitis C virus infection, with about 1 million new infections occurring each year. Because new HCV infections are usually asymptomatic, HCV is commonly unknowingly transmitted. The WHO recognizes PWID as being at greater risk of HCV infection and thus suggests targeted testing in this patient population.³

In a major step toward achieving these goals, the US Food and Drug Administration recently authorized the first point-of-care test for diagnosing HCV in settings operating under a Clinical Laboratory Improvement Amendments (CLIA) Certificate of Waiver, such as certain substance use disorder treatment facilities; correctional facilities; syringe service programs; doctor’s offices; emergency departments; and urgent care clinics. Cepheid’s Xpert HCV test and GeneXpert Xpress System detect HCV RNA and provide results in about an hour using a blood sample from the fingertip, allowing for a more rapid test-and-treat approach compared to the standard multi-step HCV testing process.⁴ However, a better understanding of the role synthetic drugs like fentanyl play in driving HCV incidence among PWID could further aid prevention and elimination efforts.¹

To determine whether illicitly manufactured fentanyl use predicts HCV and human immunodeficiency virus (HIV) incidence, investigators recruited PWID from San Diego, California, and Tijuana, Mexico, from 2020-2022. Participants underwent semi-annual interviewer-administered surveys and HIV and HCV serological rapid tests through 2024. Investigators conducted Cox regression to examine predictors of seroconversion considering self-reported illicitly manufactured fentanyl use as a 6-month lagged, time-dependent covariate.¹

Of 398 PWID at baseline, the majority were male (70%) and resided in San Diego (67%). Among the cohort, the median age was 43 years, 42% of participants reported receptive needle sharing, and 25% reported using illicitly manufactured fentanyl.¹

Investigators noted HCV incidence was 14.26 per 100 person-years (95% confidence interval [CI], 11.49–17.02), and HIV incidence was 1.29 (95% CI, .49–2.10). Upon analysis, illicitly manufactured fentanyl was associated with HCV seroconversion, with a univariable hazard ratio (HR) of 1.64 (95% CI, 1.09–2.40), and multivariable HR of 1.57 (95% CI, 1.03–2.40). Although the direction of the relationship with HIV was similar, investigators noted it was difficult to assess due to the limited number of HIV seroconversions (n = 10) and ultimately did not reach significance (HR, 2.39; 95% CI, .66–8.64).¹

"The broad shift from heroin to illicit fentanyl may be playing an important role in sharply rising HCV incidence among young people in recent years,” said Joseph Friedman, MD, PhD, a resident physician in the department of psychiatry at UC San Diego School of Medicine and the study’s first author.² “HCV elimination has been prioritized as a goal of the White House, and these findings suggest that accomplishing that goal may require taking a closer look at the role of fentanyl and other synthetic drugs in driving infectious disease risks.”

References

1. ^{Friedman JR, Abramovitz D, Skaathun B, et al. Illicit Fentanyl Use and Hepatitis C Virus Seroconversion Among People Who Inject Drugs in Tijuana and San Diego: Results From a Binational Cohort Study. Clinical Infectious Diseases. https://doi.org/10.1093/cid/ciae372}
2. ^{University of California San Diego. Illicit fentanyl use linked to increased risk of hepatitis C among people who use drugs. EurekAlert! July 30, 2024. Accessed August 6, 2024. https://www.eurekalert.org/news-releases/1053039}
3. ^{World Health Organization. Hepatitis C. Newsroom. April 9, 2024. Accessed August 6, 2024. https://www.who.int/news-room/fact-sheets/detail/hepatitis-c}
4. ^{Brooks, A. FDA Grants Marketing Authorization to Xpert HCV, First Point of-Care Hepatitis C RNA Test. HCPLive. June 27, 2024. Accessed August 6, 2024. https://www.hcplive.com/view/fda-grants-marketing-authorization-xpert-hcv-first-point-care-hepatitis-c-rna-test}