Lin Zhu explains why testing alone will not achieve HCV elimination without better access and integrated care.
Lin Zhu
Image credits: Stanford
Testing people who inject drugs (PWID) for hepatitis C virus (HCV) every 6 months could reduce HCV prevalence by up to 45%, incidence by 37%, and HCV-related deaths by 42% over 10 years, according to findings from a simulation study published July 15, 2025, in Clinical Infectious Diseases. The study was led by Lin Zhu of the Department of Health Policy at Stanford University School of Medicine.
Researchers developed a dynamic network model to simulate HCV transmission among PWID through the sharing of injection equipment. The study compared different testing frequencies paired with direct-acting antiviral therapy and measured their impact on infection prevalence, incidence, and HCV-related mortality.
In sensitivity analyses, increased coverage, defined as access to and utilization of testing and treatment, had the greatest impact on all 3 outcomes. Reinfection risk after cure significantly affected incidence, whereas lower transmission risk, higher cessation rates of injection drug use, and longer injection partnerships also reduced HCV burden regardless of testing frequency.
When asked about the challenges that limit the real-world impact of testing and treatment strategies, Zhu pointed to several barriers: “I would say limited access to and utilization of HCV care among PWID due to various factors, such as insurance restrictions, stigma associated with drug use, limited knowledge of HCV, and competing priorities such as unstable housing.”
The study findings concluded that although frequent testing combined with treatment reduces the disease burden, it is not sufficient alone to achieve HCV elimination goals among PWID without broader efforts to improve access and integration of care.
Zhu’s modeling study found that testing people who inject drugs every six months could reduce HCV prevalence by up to 45 percent.
Testing alone is not enough to achieve elimination goals without addressing barriers such as stigma, insurance limitations, and unstable housing.
Zhu emphasizes that community-based, integrated care models are crucial for improving engagement and outcomes among high-risk populations.
“Providing low-barrier, community-based, nonstigmatizing and culturally relevant HCV care for PWID is crucial for achieving HCV elimination within this population. Employing strategies such as point-of-care testing, telehealth, colocated testing and treatment, and navigation services to strengthen the HCV care continuum may enhance the effectiveness of HCV testing programs,” Zhu said.
“In addition, providing integrated care for PWID, eg, incorporating HCV care into opioid treatment programs and other harm reduction services, may produce synergy effects and help address the systemic challenges that disproportionately affect this vulnerable population,” she added.
When asked whether health departments or policy makers should prioritize testing frequency over coverage and linkage to care, Zhu explained that the answer depends on local context and is beyond the scope of the current study.
“This is an important question, but it’s unfortunately out of the scope of this study. To provide an accurate answer to your question, comprehensive modeling of the interactions among coverage, linkage to care, testing frequency, and potentially other components will be required. Different settings can have different contexts and scenarios, and hence strategic priorities could be different,” she said.
“The goal is to rapidly identify and cure the maximum number of HCV cases. If you can treat an individual before the potential transmission to the individual’s injection partners, it not only reverts one case but also prevents at least one other case. This is why testing frequency is important. However, successfully identifying and treating such cases also depends on coverage and linkage to care,” Zhu said.
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