The hepatitis D (Delta) virus (HDV), which was discovered late in the 1970s, is the smallest virus of human virology. Since it needs hepatitis B virus for its infectivity, it is also called as defective pathogen. The other important feature distinguishing HDV from other satellite viruses is its ability to independently replicate (1,2).

It is thought that the mechanism of HDV infection’s damage to the liver is immune mediated along with cytopathic effects. There are still unenlightened aspects of its pathogenesis. HDV infection is defined as coinfection or superinfection based on the condition of accompanying HBV infection.

Our country is regarded as a medium endemic region in terms of HDV infection. It is observed that anti-HDV positivity rate is higher in Eastern and Southeastern Anatolia regionswhile significant epidemiological differences exist between regions. Anti-HDV positivity was found to be 2.39% in hepatitis B surface antigen-positive patients in our society’s bus project (3). In a meta-analysis, 20% of patients with chronic HBV and 32.5% of patients with cirrhotic cases were reported to have anti-HDV positivity (4).

In this issue, Yalçın and Yalçın (5) call attention to the younger age of onset of infection and the severity of the disease in patients with HDV infection. The study evaluates 220 patients’ data and particularly the histopathological findings are noted. The most severe and rapidly progressive form of chronic viral hepatitis is chronic hepatitis D. Within 5 to 10 years, it causes cirrhosis in 70% of the cases. Risk of cirrhosis is three times higher than patients with HBV mono-infection.

Treatment options for HDV infection are limited and unfortunately cure cannot be achieved with current therapies. The goal of treatment is to suppress HDV replication, which is shown by the inability to detect HDV RNA in serum. The effectiveness of interferon therapy is limited. Pegylated interferons are the current recommended treatment regimen with limited success rates (6). Treatment should continue for at least one year. Given that restricted use of pegylated interferon in cirrhosis, liver transplantation remains the only option. Thus, it is clear that new treatments are urgently needed.

As pointed out by Yalçın and Yalçın (5), what stands out in our country for chronic hepatitis D where limited treatment options exist is young cirrhotic stage patients. As HDV depends on HBV, prevention can be achieved with hepatitis B vaccination. From this point of view, the importance of HBV vaccine becomes clearer. Particularly in the Eastern and Southeastern Anatolian Regions where both HDV and hepatitis B virus prevalences are high, hepatitis B vaccination studies should be carried out intensively.