Molecular Epidemiology of Hepatitis E Virus in Hungary (2018–2025): Emergence of Rare Subtypes and First Detection of HEV-4 in Central Europe

Hepatitis E virus (HEV) is an emerging cause of viral hepatitis in Europe, with increasing recognition in immunocompromised patients. While genotype 3 (HEV-3) is most prevalent in the region, molecular epidemiology data from Hungary have been limited. HEV strains from 118 RNA-positive patients diagnosed between 2018 and 2025 were genotyped. Next-generation sequencing yielded near-complete HEV genomes for 76 samples. HEV-3 was dominant (98.3%). Subtype 3a was the most common (34.7%), followed by 3c, 3f, and 3e. Rare subtypes (3g, 3h, 3i, 3m, 3ra) and HEV-4b were detected for the first time in Hungary. Among immunocompromised patients, 41.6% developed chronic infection. Ribavirin resistance-associated mutations G1634R and V1479I were frequently detected. In silico analysis of potential multiple infections indicated the presence of at least two HEV strains of distinct origin in six patients. Our surveillance revealed extensive genetic diversity of HEV in Hungary. The detection of rare HEV-3 subtypes and the first documented occurrence of HEV-4b in the country highlight likely viral introductions linked to the increasing international trade. Ongoing surveillance is essential in protecting high-risk groups and limiting HEV transmission in a globalized food system.