Hepatitis B

Hepatitis B is a liver disease caused by hepatitis B virus (HBV). It is transmitted by direct contact with the infected blood or body fluids such as semen, vaginal secretions, saliva, sweat, or urine. HBV is highly contagious because it can survive outside the body at least 7 days and still be capable of causing infection. In the United States, about 73,000 people were infected with HBV. In south-east Asia and parts of Africa and Middle East, the prevalence of chronic HBV infection is greater than 8%.

Chronic HBV infection is a major cause for liver cancer.

Symptoms and Diagnosis

About 30% of persons have no signs or symptoms. If symptoms occur, they occur on the average of 12 weeks (range 9-21 weeks) after exposure to hepatitis B virus. They are more likely to occur in adults than in children.

Symptoms of HBV infection include:

• yellow skin or yellowing of the whites of eyes (jaundice)
• tiredness
• loss of appetite
• nausea
• abdominal discomfort
• dark urine
• clay-colored bowel movements
• joint pain

HBV infection can be diagnosed by blood tests that detect either the hepatitis B surface antigen (HBsAg) or the IgM antibodies to the hepatitis B core antigen (IgM anti-HBc).

Vaccine

The hepatitis B vaccine is available to prevent the disease. It is safe when administered to both adults and children. Over 4 million adults have been vaccinated in the U.S., and at least that many children have received hepatitis B vaccine worldwide. 

The vaccination schedule most often used for adults and children has been three intramuscular injections, the second and third administered 1 and 6 months after the first. Recombivax HB has been approved as a two dose schedule for aged 11-15 years. Engerix-B has also been approved as a four dose accelerated schedule.

The hepatitis B vaccine can protect against clinical illness and chronic HBV infection for at least 23 years.

Treatment

For chronic hepatitis B: drug treatment with alpha interferon, peginterferon, lamivudine, or adefovir dipivoxil. These drugs should not be used by pregnant women.

Acute hepatitis B usually resolves on its own. Very severe cases can be treated with lamivudine.

Drinking alcohol can make the liver disease worse.

References:

Centers for Disease Control and Prevention, USA.
National Digestive Diseases Information Clearinghouse, USA.