Hepatitis B virus/hepatitis D virus epidemiology: Changes over time and possible future influence of the SARS-CoV-2 pandemic

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.

Prevalence of Viral Hepatitis in Unselected, Consecutively Enrolled Patients Hospitalised for SARS-CoV-2

“…Similar to HCV chronic hepatitis, we can assume that the screening for HBV was higher in the pre-pandemic period [ 17 ]. Moreover, a recent study conducted in the United States demonstrates that conducting HBV screenings for a population is cost-effective even when the estimated prevalence is low, because it can help to prevent chronic HBV infection complications [ 18 ].…”

Characterization of hepatitis virus co‐infections in a cohort of immigrants living in southern Italy

“…As regards HDV infection, in the world it is estimated that there are around 12‐60 million HBV/HDV co‐infected subjects 5,33–37 ; therefore, the HDV seroprevalence among HBV carriers varies widely in different geographical areas 5,17,34–37 . Considering the virological and clinical aspects, HBV‐HDV co‐infection is characterized by a more frequent replication of HDV infection and a severe prognosis with a more frequent development of cirrhosis and HCC compared with the HBV mono‐infected 36,38 …”

“…5,17,[34][35][36][37] Considering the virological and clinical aspects, HBV-HDV co-infection is characterized by a more frequent replication of HDV infection and a severe prognosis with a more frequent development of cirrhosis and HCC compared with the HBV mono-infected. 36,38 However, the data on the virological and clinical aspects of HCV mono-infection. In fact, they less frequently showed an asymptomatic infection and more frequently liver cirrhosis.…”

Global Distribution and Natural Recombination of Hepatitis D Virus: Implication of Kyrgyzstan Emerging HDVs in the Clinical Outcomes

“…Despite the vaccination programs against the Hepatitis B virus that have reversed the epidemiology of the HDV infection, hepatitis D, clinically associated with a poor prognosis, remains a global health issue with great medical importance [ 52 ]. HDV is highly prevalent in specific endemic areas, where the geographical distribution is linked to discrepancies in the molecular genotypes [ 5 ].…”