Is hepatitis delta underestimated?

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. [ABSTRACT FROM AUTHOR]