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Category: Gastroenterology | Hepatology

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Hepatitis B overview

Published: July 13, 2009. Updated: August 09, 2009

Originally known as serum hepatitis, Hepatitis B has only been recognized as such since World War II, and has caused current epidemics in parts of Asia and Africa. Hepatitis B is recognized as endemic in China and various other parts of Asia. Hepatitis B is transmitted through exposure to bodily fluids containing the virus. This includes unprotected sexual contact, blood transfusions, re-use of contaminated needles and syringes, vertical transmission from mother to child during childbirth, and so on.

Roughly 16-40% of unimmunized sexual partners of individuals with hepatitis B will be infected through sexual contact.

The virus that causes hepatitis B is a member of the Hepadnavirus family and it is composed of an icosahedral nucleocapsid (core) enclosing a circular, double-stranded DNA genome. The virus is unique amongst the DNA viruses in that it uses a reverse transcriptase to generate the genomic DNA to deliver to its progeny. Additionally, the DNA genome is incomplete on one strand.

Hepatitis D infection requires a concomitant infection with hepatitis B. Co-infection with Hepatitis D increases the risk of liver cirrhosis and subsequently, liver cancer.

Hepatitis B infection can lead to a chronic inflammation of the liver, leading to cirrhosis. This type of infection dramatically increases the incidence of liver cancer.


Most people who become infected as adults or older children will stage a full recovery and develop protective immunity to the virus. However, a small group of people will not manage to clear the virus from their bodies and will become chronic carriers of the virus.

There is currently no cure for Hepatitis B. Treatments are available in the form of antivirals such as lamivudine and immune system modulators such as alpha interferon. While these do not provide a cure, they can help reduce the viral load in cases where there are complications or other concomitant diseases.


A recombinant vaccine is available to prevent hepatitis B.

Many countries now routinely vaccinate infants against hepatitis B. In many areas, vaccination against hepatitis B is also required for all healthcare workers. Booster doses are recommended every five to ten years for healthcare workers.

Other at-risk groups of developing hepatitis B such as intravenous drug users are also good targets for health prevention with a Hepatitis B vaccination scheme.

Patients known to be infected with hepatitis B should be vaccinated against hepatitis A. Patients known to be infected with hepatitis C should also be vaccinated against hepatitis B. There are two reasons for this: first, hepatitis B and hepatitis C can be transmitted in the same ways; second, a person who already has one form of hepatitis will have a greater risk of severe liver damage if also infected with another form.

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