High hepatitis E (HEV) seroprevalence has been reported in the general population and in post-liver transplant (LT) cases in several regions, including Thailand, with genotype 3 being a predominant genotype. We hypothesized that HEV might persist at a subclinical level and might pose clinical risks in the post-LT period. We performed a cross-sectional study with 108 post-LT patients and found an IgG seroprevalence of 55.6%. Subsequently, 91 cases without clinical evidence of HEV-related hepatitis were enrolled in 1 year of prospective follow-up to determine clinical status, serologies and serum/feces HEV RNA every 4 months. HEV RNA was detected, indicating subclinical infections in patients with or without seropositivity, with an annual incidence of 7.7%. Our results suggest that subclinical HEV infection exists among LT patients in this high-prevalence area. Thus, clinicians should be aware of the possibility of disease reemergence and HEV viral transmission in LT patients.

Post-LT patients receiving care at the King Chulalongkorn Memorial Hospital were approached for study enrollment between October 2015 and June 2016. The study protocol is shown in Figure 1. A total of 108 patients provided a 10-mL blood sample (for serum testing for HEV IgG and IgM antibodies, and HEV RNA detection) and a fresh feces sample (for HEV RNA detection). Each patient’s demographic and clinical data, including the patient’s medical history; current medication(s), especially immunosuppressive agents; and laboratory results were retrieved from the medical records. Patients who had a previous relevant history, active acute or chronic hepatitis E, or active malignancy and those who were unable to attend regular follow-up visits were excluded from the study. After recruitment, the patients attended follow-up visits every 4 months for 12 months for a clinical assessment, basic laboratory tests, and blood/feces sample collection. All samples were stored at -70°C and simultaneously tested at the end of the study.