Hepatitis B

Hepatitis B is a liver disease caused by infection with the hepatitis B virus. In the short term this causes liver inflammation, which can cause illness and is occasionally fatal.

In most people, this ‘acute’ infection can be controlled within several months. This means the virus is no longer reproducing within the liver, and the person is no longer infectious.

In some people, the hepatitis B virus continues to grow within their liver cells. This is called a chronic infection. It can cause cirrhosis, a scarring of the liver that impairs its function.

Both acute and chronic hepatitis B infections put people at risk of developing liver cancer. The presence of the viral genome within liver cells can increase the chances that the liver cells develop genetic changes, allowing cancer development.

People who are at greater risk of developing chronic hepatitis B after initial infection include:

• Infants and young children.
• People with impaired immunity such as people infected with HIV.

One-third of the world’s population has been infected with hepatitis B virus. The virus is carried as a chronic infection by 250 million people, including more than 230,000 Australians. Chronic hepatitis B infection is more prevalent in Aboriginal and Torres Strait Islander Australians than the wider population.

More than 880,000 people die each year from the consequences of hepatitis B infection. The prevalence of hepatitis B virus globally contributes to liver cancer being one of the leading causes of cancer-related deaths. In Australia, the number of deaths from liver cancer is increasing faster than deaths from any other cancer.

Hepatitis B virus is spread between people through infected blood and bodily fluids, such as semen and saliva. When hepatitis B virus enters the body, it infects liver cells. Here the virus can replicate, and release new viruses into the blood stream.

There is a vaccine that can protect against hepatitis B virus infection. It triggers the production of antibodies to hepatitis B virus. This prevents newly acquired virus from surviving within the body.

In Australia, hepatitis vaccination is recommended for:

• Newborns.
• People working in close contact with other people, such as healthcare and childcare workers.
• People living with someone infected with hepatitis B
• People with weakened immune systems, such as people with HIV.

Unvaccinated people who may have been exposed to hepatitis B virus can be treated with antibodies to hepatitis B. These antibodies bind to hepatitis B virus in the body, preventing them from infecting cells. The antibodies are produced from the donated blood of people who have been vaccinated against hepatitis B.

Acute hepatitis B is usually a mild illness that does not require treatment.

People who have chronic hepatitis B infection can be treated with antiviral medications. These do not cure the disease. Instead they reduce the growth of the virus, and reduce liver damage. Our researchers aim to discover how the immune system can be triggered to cure chronic hepatitis B infection.

Serious liver damage caused by hepatitis B is sometimes treated by liver transplantation.