Hepatitis E Virus in Croatian Liver Transplant Recipients: Seroprevalence and One-Year Post-Transplant Surveillance from a Combined Cohort Study (2019-2022).

Hepatitis E virus (HEV) is a significant yet understudied cause of viral hepatitis among liver transplant (LT) recipients in Central and South-eastern Europe. We conducted a combined cross-sectional and prospective cohort study to determine the seroprevalence, incidence, and risk factors of HEV infection in Croatian LT recipients. A total of 766 adult LT recipients were analyzed for anti-HEV IgG and HEV RNA. Additionally, 152 patients listed for LT were followed prospectively with sampling before and up to 12 months after transplantation. Anti-HEV IgG seroprevalence in the cross-sectional cohort was 19.8%, with no active infections detected via HEV RNA. In the prospective cohort, baseline seroprevalence was 20.4%, declining post-transplant, while 3.9% of initially seronegative patients seroconverted without detectable HEV RNA. Older age and non-tertiary level of education were associated with seropositivity, while dietary and animal contact factors were not. These findings indicate a moderately high level of prior HEV exposure among Croatian LT recipients, comparable to some European regions, but a low incidence of post-transplant infection and no evidence of chronic HEV infection. Our results suggest that despite frequent exposure, clinically significant HEV infection is uncommon in this immunosuppressed population.