Hepatitis B is a viral infection that is transmitted through blood and bodily fluids. Globally, around 1 in 3 people are infected.
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 cleared by the immune system the person infected is said to have chronic hepatitis B.

The acute stage of hepatitis B infection needs no treatment but treating the chronic form is necessary to prevent fibrosis, cirrhosis and liver cancer.

Acute hepatitis B  can produce flu-like symptoms but many people have it without ever realising. If you are infected as a child you have a 95% chance of developing chronic hepatitis B. If you are an adult when you are first exposed to the hepatitis B virus, you only have a 5% chance of going on to have the chronic form of the disease.

Both forms of hepatitis B are diagnosed using blood tests:

Both tests measure the amount of viral DNA present.

  • If you have acute hepatitis B, you will have a positive blood test for hepatitis B surface antigen (HBsAg). This is a protein present on the surface of the virus.
  • If you recover from the acute infection, you will no longer test positive for the HBsAg. Your blood will contain antibodies to this antigen, showing you have become immune to the hepatitis B virus.
  • If your hepatitis B infection becomes chronic, your blood will still contain the HBsAg and it may also test positive for another antigen, the hepatitis B envelope antigen (HBeAg). This is a protein from inside the virus and its presence in the blood is a sign that the virus is dividing rapidly inside the body.
  • The amount of virus in your blood can be measured by a polymerase chain reaction test (PCR test) or quantitative HBV DNA test.

If you develop chronic hepatitis B, this can be treated and you can have regular liver function tests to make sure your liver is not becoming inflamed or scarred, and that you are not developing further conditions such as cirrhosis or liver cancer.
If any changes are detected, you may then need a liver biopsy.

Acute Hepatitis B infection

If you suspect you have been exposed to hepatitis B and you start to feel tired and under the weather, seeing your GP for a blood test will confirm if you have the hepatitis B infection. It is important for your GP to monitor you over the next few months to find out if you manage to clear the virus and develop immunity to it, or whether the virus keeps on multiplying.

Chronic hepatitis B

Early and specific treatment is important. If you develop chronic hepatitis B, the virus carries on dividing in your liver cells and the liver tissue becomes inflamed. This leads to the formation of fibrosis and eventually cirrhosis (irreversible scarring of the liver). Although it can take over 30 years, having chronic hepatitis B greatly increases your risk of severe liver damage, liver failure and liver cancer.

Drug treatment can keep the virus under control so that liver damage is prevented.

Hepatitis B treatments

Consultant Hepatologists and Specialist Liver Nurses at The London Clinic run regular outpatient clinics for patients with chronic hepatitis B. The number of effective drugs available has increased since the mid 1990s:

  • Interferon: given by injection, interferon drugs such as pegylated interferon and interferon alpha prevent the hepatitis B virus dividing and protect the liver against inflammation.
  • Antiviral drugs: taken as tablets, drugs such as lamivudine (Epivir-HBV®), entecavir (Baraclude®), adefovir (Hepsera®) and tenofovir (Viread®) are able to reduce the number of viruses in the body to virtually zero. These drugs are relatively safe and can be taken for years to keep the hepatitis B infection under control. During treatment you will need careful monitoring, particularly to make sure your kidneys are working well.

Trade names quoted are given as examples only of the drug types described, alternatives may be available.