We read with interest the articles on the treatment of hepatitis D virus (HDV) infection using pegylated interferon alpha by Niro et al.1 and Castelnau et al.,2 which showed some efficacy but low sustained virological response rates. Consequently, the accompanying editorial by Patricia Farci very impressively highlighted the urgent need for further improvement of therapeutic options for patients with delta hepatitis.3 Farci also addressed changes in the epidemiology of HDV infection in Europe during the last 2 decades, mentioning that the prevalence of HDV-infected patients among HBsAg-positive individuals had dramatically declined in Italy in the 1990s.4 However, delta hepatitis is not a vanishing disease in other countries, mainly due to immigration of people from high endemic areas. For example, the epidemiology of delta hepatitis changed significantly in Germany because of large numbers of patients migrating to Germany from Eastern Europe and countries of the former Soviet Union.
We investigated the presence of anti-HDV antibodies in sera from 2354 consecutive HBsAg-positive patients sent to the diagnostic laboratory of our department between 1992 and April 30, 2006 (Fig. 1). Overall, 253 samples (11.3%) tested positive for anti-HDV. For 144 of those, we had information on the country of birth and, as expected, only 19% of the delta hepatitis patients were born in Germany whereas 26% had migrated to Germany from Turkey and 28% migrated from Eastern Europe or countries from the former Soviet Union. Studying HDV prevalences over time showed that the percentage of patients positive for anti-HDV among individuals positive for HBsAg declined from 18.6% in 1992 to 6.8% in 1997, confirming the Italian experience.4 However and importantly, we observed no further decline thereafter. From 1999 on, between 8% and 14% of HBsAg-positive sera tested positive for anti-HDV with 13 to 27 new patients with HDV admitted to our institution each year. Although these numbers are certainly biased by a referral effect to our tertiary center, which performs more than 130 liver transplants per year, our data clearly demonstrate that HDV infection in Europe is no longer a disease found only in the Mediterranean area but also has become an important clinical consideration in central Europe. Unfortunately, oral nucleoside analogs used for treatment of hepatitis B are not effective against HDV.5–8 Thus, treatment trials such as those reported by Niro and Castelnau as well as by Erhardt et al.9 investigating the role of pegylated interferons for the treatment of HDV infection are urgently needed to develop therapies for delta hepatitis with a reasonable risk/benefit ratio. Final results of the Hep-Net/International Delta hepatitis intervention trial (HIDIT-1) that is studying 90 HDV patients will be available within a short time.10 Thus, we have to congratulate the investigators for their efforts and Farci for highlighting the importance of continuous research in HDV infection.