No evidence of hepatitis E virus-associated central nervous system infections in a Vietnamese multicenter cohort

• Multicentre cohort screened for HEV in CNS infections in Vietnam • No HEV RNA detected in 330 cerebrospinal fluid samples • Findings suggest limited role of HEV in neurological infections • Future studies should integrate serology and genotyping approaches Hepatitis E virus (HEV), traditionally associated with acute hepatitis, has been increasingly recognised as a potential cause of neurological disease, particularly in Europe and parts of Asia. However, its role in Central nervous system (CNS) infections in Vietnam has not been investigated. We retrospectively analysed cerebrospinal fluid (CSF) samples from 330 patients hospitalised with suspected CNS infections at four tertiary hospitals in Northern Vietnam. Extensive diagnostics, including CSF culture, multiplex PCR, customised PCR assays, and 16S nanopore sequencing, identified a pathogen in 27% of cases. All samples were additionally screened for HEV RNA using a nested PCR targeting the ORF1 region. No HEV RNA was detected in this study. In our previous investigations, the most common pathogens identified were Mycobacterium tuberculosis, Klebsiella pneumoniae, Streptococcus suis, Streptococcus pneumoniae, Neisseria meningitidis, Acinetobacter baumannii, Herpes simplex virus type 1 and Varicella-zoster virus. These findings suggest that HEV is unlikely to play a major role in CNS infections in this setting, although the lack of serological testing and genotyping limits interpretation. Given evidence of HEV genotype 3 circulation in Vietnam, future prospective studies combining molecular and serological approaches are warranted to clarify the potential contribution of HEV to neurological disease.