Hepatitis B: Human viral infection

It is caused by a virus. The virus is not spread by food or casual contact. It can be spread by blood or body fluids from an infected person. A baby can get it from its mother during childbirth. It can also be spread by sexual contact, reuse of needles, and transfusions of blood with the virus in it.

Infection with hepatitis B can be prevented by vaccination, where an injection is given which makes the body immune to the virus. It is recommended that all people are given a series of three vaccines over a few months when they are babies to ensure good protection against this virus. However, vaccination only provides 90% protection, it does not completely remove the risk of infection.

Some people who are infected are able to beat the virus quickly. Many people are infected for life. Usually they have few or no symptoms. Sometimes the liver is damaged severely, causing liver failure. A common symptom of liver failure is jaundice, where the person's skin and eyes turn yellow due to a build-up of body products which would normally be filtered by the liver. Another problem with hepatitis B is that it can cause cancer of the liver.

Blood tests can find signs that the liver is being damaged. If people have those signs, treatment for hepatitis B can prevent the liver damage caused by the virus. Antiviral medications are given, which prevent the virus from making copies of itself. However, once the virus is in the liver, it is not possible to get rid of the virus completely.