Recent Advances in HEV Antiviral Research (2026): From Replication System Innovation to Emerging Therapeutic Strategies

Hepatitis E virus (HEV) is a major cause of acute viral hepatitis worldwide. Its epidemiology is notably heterogeneous: HEV-1 and HEV-2 are primarily transmitted via the fecal–oral route and are prevalent in developing regions, whereas HEV-3 and HEV-4 are zoonotic genotypes, mainly associated with the consumption of contaminated meat products and represent the leading cause of sporadic hepatitis E in industrialized countries.

Figure 1: Worldwide distribution of clinical cases of HEV infection

In immunocompetent individuals, HEV infection is typically self-limiting. However, in immunocompromised populations—particularly solid organ transplant recipients—HEV-3 and HEV-4 can establish chronic infection, which may progress to liver fibrosis and cirrhosis. This clinical reality has shifted HEV from being considered a benign, self-limiting pathogen to a virus with clear unmet therapeutic needs.
Despite this, progress in HEV molecular virology and antiviral drug development has been relatively slow, and no approved virus-specific therapies are currently available for chronic HEV infection. A recent study published in Gut by a collaborative team from Peking University, Heidelberg University, and Ruhr University Bochum addresses this gap by advancing both experimental models and antiviral screening strategies, providing new tools and potential therapeutic leads for the field.

1. Moving Beyond Subgenomic Replicons: Toward Full-Length, Infection-Relevant Screening Systems

A central advance of this study is the development of a full-length HEV fluorescent reporter system. Conventional HEV drug screening has largely relied on subgenomic replicons, in which the ORF2 and ORF3 coding regions are deleted. While these systems are experimentally tractable, they fail to recapitulate key aspects of the viral life cycle, including:

To address these limitations, the authors engineered a split-GFP tag at the C-terminus of the ORF2 capsid protein, enabling real-time monitoring of viral replication within the context of the full-length genome.This design provides several key advantages: 

Figure 2: Schematic genome structure of HEV-3

Overall, this system represents a shift from reductionist replicon-based assays toward models that more closely approximate authentic viral infection. 

2. Bemnifosbuvir as a Promising Anti-HEV Candidate

Using this platform, the study screened a panel of nucleos(t)ide analogues and identified Bemnifosbuvir (BEM) as a leading candidate with robust antiviral activity.
Importantly, the value of BEM lies not only in its potency but also in several properties that are highly relevant for antiviral development: