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World J Gastroenterol. Jan 7, 2022; 28(1): 47-75
Published online Jan 7, 2022. doi: 10.3748/wjg.v28.i1.47
Transfusion-transmitted hepatitis E: What we know so far?
Carmen Ka Man Cheung, Sunny Hei Wong, Alvin Wing Hin Law, Man Fai Law
Carmen Ka Man Cheung, Man Fai Law, Medicine and Therapeutics, Prince of Wales Hospital, Hong Kong 852, China
Sunny Hei Wong, Institute of Digestive Disease and Department of Medicine and Therapeutics, the Chinese University of Hong Kong, Hong Kong 852, China
Sunny Hei Wong, Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 639798, Singapore
Alvin Wing Hin Law, West Island School, Hong Kong 852, China
Author contributions: Cheung CKM contributed to acquisition, analysis and interpretation of data/references; drafted and approved the manuscript; Wong SH contributed to analysis, interpretation of data/references; revised critically and approved the manuscript; Law AWH contributed to analysis of data/references and approved the manuscript; Law MF contributed to acquisition, analysis and interpretation of data/references, and drafted and approved the manuscript.
Conflict-of-interest statement: The authors declare no conflict of interest.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Man Fai Law, MRCP, Doctor, Medicine and Therapeutics, Prince of Wales Hospital, 30-32 Ngai Shing Street, Shatin, Hong Kong 852, China. mflaw99@yahoo.com.hk
Received: April 10, 2021
Peer-review started: April 10, 2021
First decision: June 24, 2021
Revised: July 16, 2021
Accepted: December 22, 2021
Article in press: December 22, 2021
Published online: January 7, 2022
Abstract

Hepatitis E virus (HEV) is a major cause of viral hepatitis globally. There is growing concern about transfusion-transmitted HEV (TT-HEV) as an emerging global health problem. HEV can potentially result in chronic infection in immunocompromised patients, leading to a higher risk of liver cirrhosis and even death. Between 0.0013% and 0.281% of asymptomatic blood donors around the world have HEV viremia, and 0.27% to 60.5% have anti-HEV immunoglobulin G. HEV is infectious even at very low blood concentrations of the virus. Immunosuppressed patients who develop persistent hepatitis E infection should have their immunosuppressant regimen reduced; ribavirin may be considered as treatment. Pegylated interferon can be considered in those who are refractory or intolerant to ribavirin. Sofosbuvir, a nucleotide analog, showed modest antiviral activity in some clinical studies but sustained viral response was not achieved. Therefore, rescue treatment remains an unmet need. The need for HEV screening of all blood donations remains controversial. Universal screening has been adopted in some countries after consideration of risk and resource availability. Various pathogen reduction methods have also been proposed to reduce the risk of TT-HEV. Future studies are needed to define the incidence of transmission through transfusion, their clinical features, outcomes and prognosis.

Keywords: Hepatitis E virus, Acute and chronic hepatitis, Immunosuppression, Blood transfusion, Transplantation

Core Tip: Transfusion-transmitted hepatitis E virus (HEV) is an emerging global health concern. In immunocompromised patients, chronic HEV infection increases the risk of liver cirrhosis. The prevalence of viremia and anti-HEV immunoglobulin G in asymptomatic blood donors varies widely between countries but even low concentrations of HEV in blood components are infectious, and in most countries blood donations are not routinely screened for HEV. Treatment of persistent infection includes modification of the immunosuppressant regimen followed by ribavirin. The need for screening of HEV in all blood donations remains controversial. Strategies to reduce de novo HEV infection should also be emphasized.