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World J Gastroenterol. Nov 14, 2021; 27(42): 7271-7284
Published online Nov 14, 2021. doi: 10.3748/wjg.v27.i42.7271
Hepatitis B virus/hepatitis D virus epidemiology: Changes over time and possible future influence of the SARS-CoV-2 pandemic
Caterina Sagnelli, Mariantonietta Pisaturo, Caterina Curatolo, Alessio Vinicio Codella, Nicola Coppola, Evangelista Sagnelli
Caterina Sagnelli, Evangelista Sagnelli, Department of Mental Health and Public Medicine, Section of Infectious Diseases, University of Campania Luigi Vanvitelli, Naples 80131, Italy
Mariantonietta Pisaturo, Caterina Curatolo, Alessio Vinicio Codella, Nicola Coppola, Department of Mental Health and Public Medicine, University of Campania, Naples 80135, Italy
Author contributions: Sagnelli C, Pisaturo M, Curatolo C, and Codella AV acquired, collected, extracted data, drafted, and made the final approval; Sagnelli C, and Sagnelli E designed the study, interpreted the data, drafted the article; Sagnelli C, Coppola N, and Sagnelli E, revised the article, and made the final approval.
Conflict-of-interest statement: All the authors of the manuscript declare they have no conflict of interest in connection with this paper.
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: http://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Evangelista Sagnelli, MD, PhD, Chief Doctor, Full Professor, Senior Researcher, Department of Mental Health and Public Medicine, Section of Infectious Diseases, University of Campania Luigi Vanvitelli, Via: L. Armanni 5, Naples 80131, Italy. evangelista.sagnelli@unicampania.it
Received: May 2, 2021
Peer-review started: May 2, 2021
First decision: June 12, 2021
Revised: June 20, 2021
Accepted: October 25, 2021
Article in press: October 25, 2021
Published online: November 14, 2021
Processing time: 191 Days and 18.8 Hours
Abstract

Hepatitis D virus (HDV) is a defective liver-tropic virus that needs the helper function of hepatitis B virus (HBV) to infect humans and replicate. HDV is transmitted sexually or by a parenteral route, in co-infection with HBV or by super-infection in HBV chronic carriers. HDV infection causes acute hepatitis that may progress to a fulminant form (7%-14% by super-infection and 2%-3% by HBV/HDV co-infection) or to chronic hepatitis (90% by HDV super-infection and 2%-5% by HBV/HDV co-infection), frequently and rapidly progressing to cirrhosis or hepatocellular carcinoma (HCC). Peg-interferon alfa the only recommended therapy, clears HDV in only 10%-20% of cases and, consequently, new treatment strategies are being explored. HDV endemicity progressively decreased over the 50 years from the identification of the virus, due to improved population lifestyles and economic levels, to the use of HBV nuclei(t)side analogues to suppress HBV replication and to the application of universal HBV vaccination programs. Further changes are expected during the severe acute respiratory syndrome coronavirus-2 pandemic, unfortunately towards increased endemicity due to the focus of healthcare towards coronavirus disease 2019 and the consequently lower possibility of screening and access to treatments, lower care for patients with severe liver diseases and a reduced impulse to the HBV vaccination policy.

Keywords: Hepatitis B virus/hepatitis delta virus; SARS-CoV-2; COVID-19; Hepatitis delta virus infection; Hepatitis D; Hepatitis delta virus epidemiology

Core Tip: There has been a tendency to a reduction in hepatitis D virus (HDV) endemicity in most countries in recent decades, mostly due to an improvement in population lifestyles and economic levels, to an extensive use of hepatitis B virus (HBV) nuclei(t)side analogues to suppress HBV replication and to the application of universal HBV vaccination programs. However, an increase in HDV endemicity is expected during the severe acute respiratory syndrome coronavirus-2 pandemic since healthcare is mostly diverted towards coronavirus disease 2019, with a reduced attention to liver disease, screening, access to treatment, care for patients with severe liver disease and the HBV vaccination policy.