An emerging vaccine in the arsenal to fight Hepatitis C

Blood sample, image by Jarun Ontakrai

OPINION: The COVID-19 pandemic has played a crucial role in altering the health landscape by delaying disease management for many. While statistics are questionable because of limited hepatitis C virus (HCV) testing, the Centers for Disease Control and Prevention estimates that 2.4 million Americans harbor HCV, a major cause of liver disease and cancer, with costs estimated at more than $10 billion. Nearly 50% of liver cancer cases are attributed to this blood-born RNA virus despite the availability of effective direct-acting antivirals (DAAs). These barriers to care and the fact that HCV is often undiagnosed since acute infection is generally asymptomatic until severe damage has already started only compound the challenge when knowing there is inadequate access to testing for people who inject drugs and other high-risk populations such as marginalized communities who have been historically underserved. The major health concern, which most undiagnosed and untreated patients have, is that they are unaware of potential transmission of the virus. If detected earlier and diagnosed in-time, we can avoid tangible social costs, which continue to burden individuals, families, communities, health providers and payers.

The Biden-Harris administration, as part of his fiscal year 2024 budget, has asked Congress to fund an $11.3 billion program to eliminate hepatitis C virus (HCV). The ambitious program aims to significantly expand screening, testing, treatment, prevention, and monitoring of HCV infections to save tens of billions in a few years and achieve the eradication of the disease by 2030. In an interview with HCPLive, Kris V. Kowdley, MD, director of the Liver Institute Northwest, commented “the goal might be delayed because of the opioid epidemic.” We concur with Dr. Kowdley’s implication – it would be a win-win for patients and public health if Americans were treated in a holistic and comprehensive manner with advanced prophylactic options in addition to treatment modalities.

In addition to addressing the relationship between HCV and substance use, the country can only achieve this goal of elimination through a sustainability lens. In terms of diagnostics, developing tests with high sensitivity rates has opened prospects for biosensing applications for virus identification in a cost-efficient, sensitive, rapid, and reproducible way. Yet considering the cost of diagnostics technology and treatments, vaccines are expected to be a more efficient measure if well distributed and received. Obstacles to vaccine development in the HCV field have included a limited ability to test in an animal model, the diverse nature of HCV genotypes and subtypes, the components of protective immune response, and identifying the viral antigens that can achieve the best protection against infection.

It would be a win-win for patients and public health if Americans were treated in a holistic and comprehensive manner.

As individuals involved in the field of global health research, we are very concerned with how the elimination goals for HCV are met, based firmly on humanitarian grounds. Some of us have decades of lived experience with this disease and the challenges that accompany the management of a chronic illness. Also, those already testing HCV-positive deserve to be treated and cured to prevent further transmission, progression of the disease to cirrhosis, end stage liver disease, liver transplant, and/or liver cancer (Hepatocellular Carcinoma, HCC).

Lessons learned from the pandemic for vaccine development should be applied to HCV elimination. In contrast to the expectation that viruses undergo rapid host adaptation following spillover, analysis indicates that SARS-CoV-2 lacked notable levels of observable adaptation early in the pandemic, but SARS-CoV-2 spike protein was discovered to contain important properties that are responsible and required for efficient human-to-human transmission. The development of universal vaccines that elicit broad immunity against emerging variants has been an object of investigation in this respiratory pathogen.

Noticeably, the contribution of viral and host factors determines vulnerability to infections. The exact mechanism of how these factors influence pathogenesis is of fundamental importance for vaccine development. Variants possessing unique combinations of mutations continue to emerge. To date, in understanding the drivers in the pathway of hepatitis C eradication, some genotypes have recently been found to be associated with slight resistance to very few DAA regimens.

Vaccine research and development requires identifying key factors to interrupt or neutralize antibodies that drive viral persistence. Understanding strains and variables that affect immune response are essential objectives to target effectiveness in humans.

Benedetta Pelosi, MS, Patricia Perkins, MSPH, and William M. Remak, MPH, MS, MT are all members of the Global Immunization Action Network Team (GIANT) of the California Hepatitis C Task Force.

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