Epidemiology of hepatitis D.

Hepatitis D occurs worldwide. The major victims of the hepatitis D virus (HDV) are individuals carrying the hepatitis B surface antigen (HBsAg); around 5% of the HBsAg carriers in the world are infected also by HDV. With the implementation of a hepatitis B virus (HBV) vaccination since the 1990s, the incidence of hepatitis D has consistently declined in the developed world, particularly in Southern Europe; however, immigrants from areas where HDV remains endemic are reintroducing the infection.Hepatitis D continues to ravage populations of developing and poor countries where HBV remains unchecked; action is needed to enforce HBV vaccination as effective prophylaxis not only against HBV, but against HDV as well.