Is hepatitis delta underestimated?

Abstract

Hepatitis D virus may be underestimated because it is a significant problem in HBsAg‐positive patients, especially those who inject drugs, have HIV or HCV co‐infections and/or live in certain endemic regions. In the past few decades, the prevalence of HDV was expected to have decreased as a result of improvements in public healthcare policies and universal HBV vaccination programs. However, HDV has continued to spread in low‐income countries, with local outbreaks and migration to less endemic areas, so that its prevalence has remained stable or even increased in certain regions. As a result, research has been focused on the epidemiology of HDV. Contradicting data from three large recent meta‐analyses have reported that the prevalence of HDV may be between 0.16% and 1.00% in the global general population, and 4.5% and 14.6% in HBsAg‐positive patients, with an estimated 12 to 70 million HDV patients worldwide. The exact prevalence and estimated number of HDV patients is still a subject of debate for several reasons, including the unreliable assessment of the infection and a lack of real‐world screening. HDV infection is associated with an increased risk of progression to cirrhosis and the development of HCC compared to patients with HBV mono‐infection, a risk which is even higher in patients with HIV co‐infection. Morbidity and mortality from HDV‐related cirrhosis should not be overlooked. In conclusion, hepatitis D virus is probably underestimated and certainly underdiagnosed, and screening for HDV should be performed in all HBsAg‐positive patients in clinical practice.

Molecular epidemiology and clinical characteristics of hepatitis D virus infection in Canada

“… 22 both describe considerably higher prevalence among hepatology clinic attendees, at 16.4% and 13.02%, respectively. This discrepancy may be a result of meta-analyses study selection 12 or screening bias among the Canadian clinic population, but the publicly funded healthcare system in Canada may also influence the prevalence findings. It is plausible that access to universal healthcare may result in a relatively lower ratio of HBV-referred patients having severe liver disease at the time of referral.…”

“… 11 The true prevalence and distribution of HDV seroprevalence and active infection is uncertain, with estimates that vary significantly. 12 , 13 One study established a global HDV prevalence estimate at 12 million infected individuals, 14 or approximately 4.5% of HBsAg-positive individuals. Canada has an estimated HBV infection rate of approximately 13.4 per 100,000 (2017 data 15 ) with >250,000 chronically infected Canadians living with HBV.…”

HERACLIS‐HDV cohort for the factors of underdiagnosis and prevalence of hepatitis D virus infection in HBsAg‐positive patients

“…4 In such an uncertain epidemiological status, the epidemiology of hepatitis D virus (HDV) is even more undefinable, as HDV screening rates among diagnosed hepatitis B surface antigen (HΒsAg) positive individuals seem to vary widely usually ranging at low levels even in epidemiologically well organized countries. 5,6 Thus, the global HDV prevalence has been debatable and was declared uncertain by the 2017 WHO Global Hepatitis Report. 7 The global prevalence of HDV infection, which is usually based on the detection of antibodies against HDV (anti-HDV), has been reported to vary widely in the estimations of different systematic reviews, 5 since the global number of HDV infected individuals has been suggested to range from 12 to more than 60 millions.…”

“…5,6 Thus, the global HDV prevalence has been debatable and was declared uncertain by the 2017 WHO Global Hepatitis Report. 7 The global prevalence of HDV infection, which is usually based on the detection of antibodies against HDV (anti-HDV), has been reported to vary widely in the estimations of different systematic reviews, 5 since the global number of HDV infected individuals has been suggested to range from 12 to more than 60 millions. [8][9][10] At the same time, it is well accepted that HDV underdiagnosis remains • Anti-HDV prevalence varies throughout Greece being higher in patients born abroad with younger age, parenteral drug use and advanced liver disease.…”

“…common varying widely among different countries and even among different areas of the same country, which may face different barriers for HDV diagnosis. 5,11 Given that HDV requires for infection the helper functions of HBV and in particular the presence of HBsAg, HDV diagnosis is restricted in HBsAg-positive cases. [12][13][14] HDV infection, either as co-infection with HBV or as superinfection in individuals with pre-existing chronic HBV infection, is associated with increased morbidity and mortality.…”