HEPATITIS B - A form of viral hepatitis, known as serum hepatitis, because it is commonly spread through contact with infected blood products (transfusion). May also be spread sexually or from mother to infant. Hepatitis B can cause a much more severe infection than hepatitis A, and, can occur as an asymptomatic "carrier" state, a chronic infection, or as cirrhosis of the liver. Those at risk (IV drug abusers, health care workers, dialysis patients, transfusion recipients, and homosexuals) should be immunized with hepatitis B vaccine.