First Things First: Why We Need Worldwide Improvement in Screening for HDV

Since its identification in the late 1970s, the hepatitis delta virus (HDV) has presented therapeutic challenges worldwide. It is of great importance to diagnose (and subsequently treat) patients infected with HDV as early as possible to avoid the severe consequences attributable to living with HDV. Here’s my take on why we need to improve screening and diagnosis of patients with HDV around the world.

Identifying the HDV Population
Most patients diagnosed with HDV live in or have emigrated from highly endemic regions of the world. In Istanbul, where I live, HDV is prevalent among immigrants. I was not expecting to see so many patients with HDV in Istanbul, but these patients typically are from neighboring countries such as Georgia and Moldova or regions of Central Asia, or have immigrated from southeast or east Turkey.

Vaccination Status
Because HDV can be contracted only along with hepatitis B virus (HBV) or after someone is already infected with HBV, it is important to vaccinate people against HBV as a means of preventing infection with both viruses.

In Turkey, many people―including children and teenagers―emigrate from Syria, and they all are supposed to have received infant vaccinations against HBV. However, many people are leaving Syria due to an ongoing war, and war creates huge barriers to adequate healthcare infrastructure. In a study of Syrian refugees younger than 18 years of age in eastern Turkey, the HBV prevalence was >4%.

Based on information like this, we know that universal infant vaccination against HBV is not occurring, and it is important to screen immigrants from endemic countries for both HBV and HDV.

Importance of Screening
HDV continues to be the most severe form of viral hepatitis―but with a twist. The twist is that there currently is a spectrum of disease severity in patients with HDV.

In the past, HDV may have been a more uniformly severe disease. Fulminant hepatitis was seen more often with HBV/HDV coinfection compared with HBV monoinfection. In addition, the path to liver cirrhosis and hepatic decompensation was much faster in patients with chronic HDV infection. In those days we did not see much hepatocellular carcinoma (HCC) because many patients apparently did not live long enough to develop it.

Today, the presence of HDV still causes more severe liver disease, but several studies―particularly from Europe―have shown that some patients present with a milder form of disease or that the disease activity slows down after reaching a certain stage. Overall, patients may live long enough to develop HCC. Slower disease activity may be due to slower turnover of the virus in the community and associated with less virulent HDV strains.

The natural history of HDV depends on many factors, including HBV and HDV genotype, HBV/HDV coinfection vs super infection, and many others. Although these variables may create a spectrum of disease severity across individuals with HDV, the consequences of living with HDV are undoubtedly severe. If identified early via universal screening, we can prevent the progression to more severe liver disease and HCC.

My Call to Action
Based on the severity of HDV, we need to improve on finding and diagnosing patients with this infection so that we can link them into treatment early. We also need to identify our patients with HDV so that we can provide appropriate surveillance for cirrhosis and HCC.

Your Thoughts?
What barriers do you experience in identifying your patients with HDV? Answer the polling question and join the conversation by posting a comment.