The hepatitis B virus is a major cause of serious, life-threatening liver disease, including liver cancer and cirrhosis (scarring of the liver caused by long-term liver damage).
Many people do not show any symptoms, and may not even know they have been infected. Even so, during their infection, they can pass the disease on to others.
Hepatitis B sometimes causes flu-like symptoms, such as tiredness, general aches and pains, headaches and a high temperature. It can also lead to loss of appetite, sickness, diarrhoea, yellowing of the skin and eyes (jaundice), and pain in the upper right-hand side of the tummy (abdomen).
If they do appear, symptoms will normally begin two to three months after exposure to the virus, and last for several months. But the infection can persist for longer, and may never go away. These chronic infections can lead to serious liver problems.
The HepB virus is transmitted by blood and bodily fluids; in the UK this occurs mainly through sharing needles for drugs such as heroin, or through unprotected sex.
An infected mother can pass HepB on to her baby during birth. Infection in this way usually leads to long-term infection, and puts the child at risk of serious liver disease later in life.
There is a vaccine that gives protection against the HepB virus. In the UK this is currently only given to those at the greatest risk, as identified by the screening programme offered to all pregnant women. Across the UK, around 1 in every 700 mothers are found to be infected with HepB. Babies born to infected mothers are exposed to the virus during birth, and urgently need protection. They should therefore be vaccinated within 24 hours of birth, and then go on to complete a course of 3 further doses at 1 month, 2 months, and 12 months of age. Since the disease is so serious, the World Health Organization has said that all babies in the world should be protected by the HepB vaccine. The UK is expected to introduce the vaccine for all babies in the near future.
Babies born to women thought to be particularly infectious based on the screening result should be given HepB immunoglobulin at birth, alongside vaccination. This provides immediate, temporary protection while the baby develops their own immunity through the course of four immunisations during the first year of life.