What is hepatitis B?

Hepatitis B is a type of viral hepatitis that affects 1 in 3 people alive in the world today.

Where is hepatitis B most common?

In the UK, there are around 200,000 people infected by hepatitis B and who need drug therapy. In general, rates of hepatitis B infection are low here, as they are throughout Western Europe, the USA and Australia, with less than 2% of the population infected.

Most cases are concentrated in Asia, which includes China and Thailand, sub-Saharan Africa and South America. Between 10% and 25% of the population in these regions may have chronic hepatitis B. Eastern Europe, some countries in South America and in North Africa have infection rates up to about 7%.

The number of cases of hepatitis B is increasing. This is a blood-borne and sexually transmitted virus. The greater access to travel means that it has the potential to spread rapidly.

How is hepatitis B transmitted?

In areas where hepatitis B is very common, most transmission occurs from mother to baby as the baby is exposed to the mother’s blood during birth. Children playing together can also pass on the virus when they get cuts and grazes.
In areas where hepatitis B is less common, other routes of transmission become important:

  • Sexual Contact
  • Sharing needles and illegal drug use.
  • Receiving contaminated transfused blood or blood products.*
  • Dental or medical treatment with contaminated needles or equipment.*
  • Tattooing or body piercing with contaminated needles or equipment.
  • Sharing personal toiletry items (such as a razor or a toothbrush).

* More likely in countries where hygiene standards are not high, but unlikely in the UK, Western Europe and the USA.

Preventing hepatitis B with a vaccine

In high prevalence countries, such as in the Far East, all babies are vaccinated at birth to prevent viral transmission either at birth or in later life. People known to be at risk of becoming infected with hepatitis B can have the hepatitis B vaccine later in life too. In all developed countries, healthcare workers are vaccinated against the virus, as should all close relatives of patients who have hepatitis B.

The hepatitis B vaccine is normally given in 3 doses. The second is given one month after the first, and the third, 5 months after that. If the vaccine is given just after you may have been exposed to the virus, you can have a faster schedule, with the second dose after 7 days and the third after 21 days.

In all cases, you will need to have a blood test to make sure the vaccine has worked and that you have developed antibodies to hepatitis B. The immunity can wear off quite quickly, and some people need a booster within 5 years.

Acute and chronic forms of hepatitis B

When someone is first infected with hepatitis B, they have the acute form of the infection for about 6 months. After that, if the virus has not been beaten and cleared by the immune system, the person infected is said to have chronic hepatitis B.
Not all cases of acute hepatitis B become chronic. It is more likely if you are exposed as a child, with 9 out of 10 children infected before the age of one developing chronic hepatitis B. Fewer than 5 in every 100 adults who catch the infection develop the chronic form.

Acute hepatitis B often causes no symptoms, but it can lead to flu-like symptoms and an upset stomach. Chronic hepatitis B is also often silent, but the infection damages the liver in the long-term, leading to higher rates of cirrhosis of the liver and liver cancer.