Hepatitis B
Hepatitis B is a viral infection that causes inflammation of the liver. It is caused by the hepatitis B virus (HBV), which attacks the liver cells. Approximately 60% of people infected do not go on to develop an illness as the body successfully fights off the virus. These people are then immune to the virus and can not contract hepatitis B again.
When illness does occur, hepatitis B can be acute (short term) or chronic (long term). Acute hepatitis B (affecting approximately 20% of people infected) is usually a mild illness from which people fully recover. The chronic form of hepatitis B (affecting approximately 20% of people infected) is more serious and can lead to complications such as liver failure and liver cancer.
In New Zealand hepatitis B most commonly occurs in Maori, PacificIsland and Asian ethnic groups. A safe, effective vaccine against hepatitis B is available, and has been part of New Zealand’s national immunisation schedule since 1985.
The hepatitis B virus is spread from person to person in blood or body fluids. The virus is highly infectious and modes of transmission include:
- Infected blood or other body fluids getting into cuts and scratches
- Sexual contact
- Sharing personal items such as toothbrushes and razors
- Sharing injecting drug equipment
- Tattooing, acupuncture and ear piercing if equipment is not sterilised
- From mother to her unborn baby
Hepatitis B has also been known to spread through blood transfusions. However, all blood donated in New Zealand has been screened for hepatitis since 1992.
A diagnosis of hepatitis B is confirmed by blood tests. The detection of the hepatitis B virus, or antibodies to the virus, in blood tests, indicates hepatitis B infection. During the early stages of acute hepatitis B blood tests may show a significant change in liver function.
If the hepatitis B virus is present in the blood for longer than six months, but the person has not developed the acute illness, chronic hepatitis B is diagnosed.
Approximately one in five adults (and a smaller proportion of children) infected with the hepatitis B virus will develop the full-blown illness, then go on to make a full recovery. This is known as acute hepatitis B. Whilst usually a mild illness, the range and severity of symptoms experienced differs between individuals and depends on factors such as their age and general health.
Symptoms include:
- Fatigue
- Fever
- Headaches
- Jaundice (yellowish skin and eyes)
- Weight loss
- Decreased appetite
- Nausea and vomiting
- Bad breath and bitter taste in the mouth
- Dark brown urine
- Pale coloured bowel motions
- Pain in the right side of the abdomen, just below the ribs.
Acute hepatitis B has a long incubation period (the time from infection to when the illness occurs), being on average two to three months. The most infectious period is from several weeks before symptoms appear until several weeks or months later.
Most people who have a mild illness will recover completely within four to eight weeks, though in cases where the condition was more severe, recovery can take several months. In rare cases acute hepatitis B can cause serious liver damage and in very rare cases it can be fatal
After infection with and recovery from acute hepatitis B, the person is immune and is not able to pass the virus on to others.
Approximately one in five people infected with the hepatitis B virus will develop chronic hepatitis B and become carriers of the virus. The majority of people who are carriers of hepatitis B contracted the virus as babies or young children. It is unusual for adults to become chronic carriers.
Chronic hepatitis B sufferers do not get ill at the time of infection with the hepatitis B virus and most will probably never suffer any negative effects. However up to 25% of hepatitis B carriers go on to develop liver damage later in life. Over many years this damage to the liver may cause cirrhosis, a serious liver disease, which creates a further risk of liver cancer.
Even though they may not become unwell, and may not even know they have had the virus, chronic carriers can pass the virus on to other people.
It is estimated that there are currently up to 45 000 chronic hepatitis B sufferers in New Zealand.
Acute hepatitis B
While there is no cure for acute hepatitis B, treatment for it can be given within 24 hours to one week of exposure to the virus. Injections of immune globulin (a concentrated blood protein) can be given to help the body to develop antibodies that fight the hepatitis B virus. While this may not stop the disease developing altogether, it does enhance the body's ability to fight the virus.
If symptoms develop, an important part of treatment in rest. A nutritious diet and maintaining an adequate fluid intake is also recommended. Avoiding alcohol and medications is important, as these are metabolised by the liver.
Chronic hepatitis B
Chronic hepatitis B sufferers should maintain a healthy diet and avoid alcohol and unnecessary medications.
Regular blood tests to monitor the functioning of the liver will be recommended. Biopsies of the liver may also be recommended to monitor the seriousness of any liver damage over time.
Medications available to help treat those with chronic hepatitis B include:
Interferon
This is a synthetic protein that stimulates the immune system to reduce the speed at which the hepatitis B virus replicates. It is given as a course of injections over several months. Side effects can be troublesome and include flu-like symptoms such as muscle aches, fatigue and a feeling of being generally unwell.
Lamivudine
This medication works by stopping the hepatitis B virus from replicating. It is given in tablet form over several months or even years. It has fewer side effects than Interferon but, over time, the body can develop a resistance to the medication.
Adefovir (Hepsera)
This medication is used when hepatitis B carriers with serious liver disease have become resistant to lamivudine. It usually needs to be taken long term.
While these medications can be effective, they are only successful in a moderate proportion of cases and are limited by side effects and resistance.
Immunisation
Immunisation is a safe and effective way of preventing the spread of hepatitis B. Since 1985 the vaccine has been part of the national immunisation schedule. It is given to babies at six weeks, three months and five months. Babies born to mothers with hepatitis B will also be given an extra dose of the vaccine at birth.
In adolescents, two doses of the vaccine are recommended, with the second dose four to six months after the first. In adults, three doses of the vaccine are recommended, with the initial dose followed by doses one month and six months later. These doses can be given more closely together if more rapid protection is required.
Hepatitis B immunisation is recommended and publicly funded for the following groups:
- All children up to their 16th birthday
- Household and sexual contacts of known carriers.
Hepatitis B immunisation is recommended, but not publicly funded for the following adults:
- Those at risk because of their occupation eg: nurses, doctors, dentists
- Those undergoing renal dialysis
- Homosexual men
- Intravenous drug users
- Commercial sex workers
Minimising the risk of contraction
Measures that can help prevent the spread of the hepatitis B virus include:
- Teaching children not to touch others blood or wounds
- Covering cuts, scratches and grazes
- Not sharing personal items such as razors and toothbrushe
- Practising safe sex.
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Further Support and Information
The Hepatitis Foundation can offer support and information on hepatitis B.
The Hepatitis Foundation
PO Box 647
Whakatane
Freephone: 0800 33 20 10
Ph: (07) 307 1259
Fax: (07) 3071266
E-mail: hepteam@hepfoundation.org.nz
Website: www.hepfoundation.org.nz
For information about hepatitis B vaccination, consult a doctor or contact the:
Immunisation Advisory Centre
Freephone: 0800 466 863
Website: www.immune.org.nz
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References
Anderson, K.N., Anderson, L.E. & Glanze, W.D. (eds.) (2006) Mosby’s medical, nursing, & allied health dictionary (6th ed.) St. Louis: Mosby-Year Book, Inc.
Cramer, D. A., Odle, T. G. (2006) Hepatitis B. The Gale Encyclopedia of Medicine. Third Edition. Jacqueline L. Longe, Editor. Farmington Hills, MI: Thomson Gale.
Everybody (2003). Hepatitis B Virus. Auckland: MediMedia (NZ) Ltd.
http://www.everybody.co.nz/page-2a8cfdc9-9d4f-4d24-8047-decdf6aed046.aspx
Finlayson N.D.C., Hayes P.C., Simpson, K.J. (1999) Diseases of the liver and biliary system. In Haslett C., Chilvers E.R., Hunter J.A.A., & Boon N.A., (eds.) Davidson’s Principles and Practice of Medicine (18th ed.) (p683-736) Edinburgh: Churchill Livingstone
Ministry of Health (2002) Immunisation handbook Wellington: Ministry of Health
Ministry of Health (1999) Hepatitis B and You: Advice for carriers and their families. Pamphlet. Wellington Ministry of Health
Last Reviewed - 30/5/07