Hepatitis B is caused by a virus that attacks the liver. The hepatitis B virus can cause lifelong infection, cirrhosis (scarring) of the liver, liver cancer, liver failure and death.¹

The hepatitis B virus is transmitted by contact with blood or body fluids of an infected person.

• Developing countries:² Most infections occur from infected mother to child, from child-to-child contact in household settings and from reuse of unsterilized needles and syringes. In many developing countries, almost all children become infected with the virus.
• Industrialized countries:² Mother-to-infant and child-to-child transmission has dropped substantially, thanks to childhood hepatitis B vaccination programs. Primary means of transmission in these countries is through sexual activity and injected drug use. In addition, hepatitis B virus is a major infectious occupational hazard of health workers, and most health care workers have received hepatitis B vaccine.

The hepatitis B virus is not spread by contaminated food or water, and cannot be spread casually in the workplace.²

The hepatitis B virus attacks the liver, causing lifelong infection, cirrhosis (scarring) of the liver, liver cancer, liver failure and death.¹

A person with hepatitis B infection may or may not have symptoms. Symptoms occur in about 70 percent of patients and are more likely to occur in adults than in children. Symptoms may include:¹

• Yellow skin or yellowing of the whites of your eyes (jaundice)
• Tiredness
• Loss of appetite
• Nausea
• Abdominal discomfort
• Dark urine
• Clay-colored bowel movements
• Joint pain

If symptoms occur, they occur on the average of 12 weeks (range 9-21 weeks) after exposure to the hepatitis B virus.¹

A blood test is the only way to know for sure. Blood is tested for the presence of specific anti-viral antigens or antibodies.²

The hepatitis B surface antigen, HbsAg, will be detected in an infected person's blood on the average of 4 weeks (range 1-9 weeks) after exposure to the virus. About one out of two patients will no longer be infectious by seven weeks after onset of symptoms. Patients who do not remain chronically infected will be HBsAg-negative by 15 weeks after onset of symptoms.¹

A blood test is the only way to know for sure. Blood is tested for the presence of specific anti-viral antigens or antibodies.²

The hepatitis B surface antigen, HbsAg, will be detected in an infected person's blood on the average of 4 weeks (range 1-9 weeks) after exposure to the virus. About one out of two patients will no longer be infectious by seven weeks after onset of symptoms. Patients who do not remain chronically infected will be HBsAg-negative by 15 weeks after onset of symptoms.¹

There is no specific treatment for acute viral hepatitis B. Chronic hepatitis B may be treated with antiviral drugs.^{1 2} However, many of those infected in developing countries do not have access to these drugs.

Patients with cirrhosis are sometimes given liver transplants, with varying success. It is preferable to prevent this disease with vaccine than to try and cure it.²

Hepatitis B is preventable with safe, effective vaccines that have been available since 1982. If the vaccine is administered before infection, it prevents the development of the disease and the carrier state in almost all individuals. It has been given to more than 500 million persons and has proved one of the safest, most immunogenic and effective vaccines.²

Because the hepatitis B virus is transmitted by contact with blood, it can be transmitted through blood transfusions. Blood donors could be infected with hepatitis B without knowing it, because:

• Hepatitis B often does not have symptoms in 30 percent of patients¹
• It can take an average of 12 weeks (range 9-21 weeks) after exposure to the hepatitis B virus to experience symptoms¹

Blood donation screening for the hepatitis B surface antigen, HBsAg, was mandated in the U.S. in 1972. The introduction of screening for the antibody to the hepatitis B surface antigen, anti-HBc, in the U.S. in 1986 has efficiently excluded those donors who were persistent, low-level carriers, and those in the window period of acute infection.²

In the U.S., the current overall risk of acquiring hepatitis B after a transfusion is about one in 50,000 per recipient. However, donors who are in the early incubation stage of their disease, capable of transmitting hepatitis B, remain unidentified with current techniques.²