Per CDC:
Hepatitis D is a liver infection caused by HDV. HDV is known as a "satellite virus" because it can only infect people who are also infected by the hepatitis B virus (HBV). HDV can cause severe symptoms and serious illness that can lead to liver damage and even death.
Because hepatitis D is not a nationally notifiable condition, the actual number of hepatitis D cases in the US is unknown.
KEY POINTS
Hepatitis D is a liver disease caused by the hepatitis D virus (HDV).
Only people with hepatitis B can contract HDV.
Hepatitis B vaccination provides protection against hepatitis B and, therefore, against hepatitis D.
People with hepatitis D show severe symptoms of the disease.
Hepatitis D is considered uncommon in the United States.
To learn more visit: Hepatitis D Basics | Hepatitis D | CDC