Usefulness of dried blood spot samples for monitoring hepatitis C virus infection in people who inject drugs

A study of people who inject drugs evaluated a minimally invasive test based on dried blood spots (DBS) to detect hepatitis C virus (HCV) infection. demonstrated the use of DBS samples for HCV RNA detection and genotyping to effectively assess recovery after treatment and to differentiate reinfection from treatment failure. The findings support the feasibility of decentralizing treatment and post-treatment monitoring for people who inject drugs, who often face challenges in accessing the healthcare system. The study published in Journal of Medical Virology, as part of a project supported by the Conquering Hepatitis with Microlimine (CHIME) program and a PFIS grant. Investigators from various research institutions collaborated on the project, including the Clinical Virology and Novel Diagnostic Tools Research Group, led by Dr Elisa Martro, of the Research Institute of Germans Trias i Pujol (IGTP) and Dr Sabella Lens of the Viral Hepatitis Group of the Hospital Clinic.

Toward the eradication of hepatitis

In line with the strategy proposed by the World Health Organization to eliminate viral hepatitis as a threat to public health by 2030, and the plan for the prevention and control of hepatitis in Catalonia, in which Dr. Martro is actively involved, her group has focused for years on simplifying the diagnosis of hepatitis C through the development and verification Validate an assay that can detect virus RNA using DBS samples. These minimally invasive samples can be collected in harm reduction centers or drug dependence care and follow-up centers (known as CAS in Catalan), improving access to hepatitis C diagnosis for populations at risk, such as people who inject drugs. While this new test has shown good clinical performance as a diagnostic tool for detecting HCV RNA before treatment in previous studies by the Virology and New Diagnostic Tools Research Group, the use of DBS samples as a test for cure or for detecting reinfection after treatment has not been evaluated.

A multidisciplinary research group has been able to pursue a project with a new model of hepatitis C care, based on point-of-care diagnosis, treatment and follow-up of reinfection at the REDAN La Mina Center for Harm Reduction. Since 2019, nearly 750 people who inject drugs have been tested through this initiative, which was designed by Dr. Sabella Lens of the Viral Hepatitis Unit at the Hospital Clinic, in collaboration with the Research Group Clinical Virology and Novel Diagnostics at the Research Institute of Germans Trias i Pujol (IGTP), led by Dr. The project has the support of the Conquering Hepatitis with Microliminals (CHIME) program from Gilead Sciences awarded to Dr. Lens, as well as a PFIS grant from the Instituto Salud Carlos III and the Fondo Social Europeo Foundation awarded to Ana Nott, a member of Dr. Martro’s group, and is in line with the strategy WHO Global Health, which aims to eliminate hepatitis C as a public health problem by 2030.

A model of decentralized care

In this project, Dr. Martró’s group aimed to evaluate the clinical performance of a previously developed HCV-RNA assay based on DBS, for treatment evaluation and detection of recurrent viruses after in situ treatment in a harm reduction center, compared to HCV-RNA. Commercially available HCV-RNA point-of-care test. Furthermore, they sought to assess the possibility of distinguishing reinfection from treatment failure by HCV genotyping from baseline and follow-up DBS samples. Typically, these evaluations (treatment and reinfection) are done using venipuncture blood samples collected in health care settings, which can be difficult for people who inject drugs who often have limited access to the health care system. Recently published results demonstrate how collecting pre- and post-treatment DBS samples can simplify these assessments in decentralized testing and treatment programmes.

“The success of the CHIME project lies in the decentralized diagnosis and treatment provided at REDAN La Mina. A nurse trained in hepatology assessments was included in the study to enroll and visit the participants. The Hepatologists at the Hospital Clinic also reviewed each case and prescribed the decentralized treatment. In addition, Dr. Martro’s group implemented Detection and sequencing of hepatitis C from DBS samples collected before and after treatment.This pilot program includes on-site diagnosis of viral hepatitis in less than an hour, treatment at the same center, and follow-up to assess reinfection”states Dr. Lens.

Discovery just got easier

Re-infection is common in people who inject drugs and must be treated to prevent further transmission of the virus. During early infection, low levels of virus may be present, making its detection in DBS samples difficult, as they contain only a small amount of blood. Of the 193 post-treatment DBS samples tested, the DBS-based assay showed a specificity and sensitivity of 100% ranging from 84% to 96% based on a relevant difference. burden or viral load cutoff, rates similar to the cure test (three months post-treatment). It must be borne in mind that among patients with recurrent viral infections after treatment, one-tenth had reduced viral loads. Moreover, HCV genotyping allowed the researchers to classify 73% of cases of infection with the virus as either reinfection or treatment failure.

DBS samples were collected before antiviral treatment and after treatment if recurrent virus was detected by a commercially available point-of-care assay. Anna Nott, first author of the article (which will be part of her PhD thesis), explains this “Using DBS technology allowed us to sequence the virus before and after treatment and compare the sequences to determine if the virus was the same (indicating treatment failure) or if it was different (indicating reinfection). This information enabled the hepatologist to decide on the most appropriate combination. Antivirals for second therapy”.

The research shows the possibility of using DBS samples to determine treatment and to differentiate reinfection from relapse after anti-HCV treatment in people who inject the drug. The use of DBS samples allows for the possibility of decentralizing treatment and follow-up, and improving access to care for these people. However, Dr. Martro points out that “A small number of patients had low viral loads, which can hinder viral detection and genotyping in deep brain stimulation. As a result, repeat testing (eg every six months) is recommended for individuals at risk of reinfection with HCV. “.