Hepatitis B virus infection (HBV)

What is Hepatitis B?

Hepatitis B is a virus which can infect the liver. It may also be referred to as Hep B or HBV. It is relatively uncommon in Ireland with a prevalence of less than 1 in 200. Many people with hepatitis B develop an acute infection. Acute infection may be mild or cause more serious infection with fever, fatigue, jaundice (yellow eyes and skin) requiring hospitalisation. Some people develop a lifelong, chronic hepatitis B infection. Those who contract hepatitis B in infancy (e.g. from their mother at delivery), are particularly at risk of chronic hepatitis B. Chronic hepatitis B may cause liver cirrhosis (severe scarring), liver failure, liver cancer. 

Hepatitis B Transmission

Hepatitis B is transmitted via exposure to different bodily fluids such as blood, sweat, tears, semen, vaginal secretions of a person who has active hepatitis B infection. There must be contact between infected bodily fluids and broken skin or mucus membranes for the virus to be transmitted. 

Examples of how hepatitis B may be transmitted include: 

• During delivery of a new-born from an infected mother

• Sexual intercourse with an infected partner

• Sharing contaminated needles

• Blood transfusion in some countries (all blood for transfusion in Ireland is tested for hepatitis B)

To reduce the risk of transmission, it is recommended that people at risk of hepatitis B infection should get vaccinated. This includes, but is not limited to, those at risk of occupational exposure (e.g. nurses, doctors, Gardaí, soldiers), family and household contacts of those with hepatitis B, intravenous drug users, transplant recipients. 

Vaccination against Hepatitis B

Vaccination against hepatitis B can dramatically reduce the risk of transmission and is commonly available. It is not a live vaccine but made from a recombinant hepatitis B antigen. This means the vaccine does not contain the actual virus. Hepatitis B therefore can’t be contracted from the vaccine. 

The hepatitis B vaccine forms part of the “6 in 1” vaccine given to babies at 2, 4, and 6 months in Ireland. 

Adults can also get vaccinated against hepatitis B. This requires a 3 or 4 dose course, generally spread over several months. 

Your response to the vaccine can be measured in the blood. In those who achieve an adequate response it is estimated that they will be protected from significant hepatitis B infection for about 20 years, or potentially even longer. A minority of people will have an inadequate response to the vaccine. They may require larger or additional doses. 

Hepatitis B and Pregnancy

If you have chronic hepatitis B and become pregnant, or are planning a pregnancy, it is important to tell your doctor. Some women require treatment throughout pregnancy, others in their last trimester and for up to 3 months after delivery, and others still none at all. It will depend on the level of the virus, liver enzyme test results, and the presence of fibrosis (scarring). Some women may need to have their medication changed to drugs such as tenofovir which have been studied in pregnancy. 

Perinatal transmission of hepatitis B occurs mainly at delivery. It is possible to reduce the risk of transmission of hepatitis B to the baby from over 90% to less than 10%. This is done by vaccinating the baby and giving the baby a special treatment called hepatitis B immunoglobulin within 12 hours of birth. 

Breast feeding is not prohibited in untreated women or those on tenofovir treatment. 

Management of Hepatitis B

Acute hepatitis B is often self-limited and does not require specific treatment other than resting, maintaining nutrition and fluid intake. Those with more severe symptoms (especially jaundice) may require hospitalisation. 

All those with chronic hepatitis B infection need regular monitoring and so should be linked in with liver services. There are medications available to control chronic hepatitis B infection, but at present none are available to cure hepatitis B. Some people don’t require medication or may only require it for several years. Others require lifelong treatment. Some people require regular liver scans (approximately every 6 months) as they are at particular risk of liver cancer. This includes those of African or Asian origin, and those with cirrhosis. 

Hepatitis B Reactivation

Those who have had acute hepatitis B previously, whose infection has resolved, remain at risk of reactivation. They may require hepatitis B treatment to prevent reactivation if going on chemotherapy or immunosuppression for cancer, autoimmune disease, transplantation. 

Useful links:

https://www.hse.ie/eng/health/immunisation/pubinfo/pcischedule/vpds/hepb/