Hepatitis B is a viral infection that causes inflammation of the liver (hepatitis). It is caused by the hepatitis B virus, which attacks the liver cells causing either temporary (acute) or persistent (chronic) hepatitis.
Acute hepatitis B produces obvious symptoms from which people fully recover. Chronic hepatitis B symptoms are more subtle and treatment is focused on preventing long-term liver damage and transmission of the disease.
The introduction of universal infant vaccination in 1988 has contributed to a dramatic decline in the number of new cases of hepatitis B in New Zealand.
Many people infected with hepatitis B 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 cannot contract hepatitis B again.
When illness does occur, it is either acute (short-term) or chronic (long-term). Acute hepatitis B is usually a mild illness from which people fully recover. The chronic form of hepatitis B is more serious and can lead to complications such as liver fibrosis or cirrhosis (scarring of the liver), liver failure and liver cancer.
is another form of viral hepatitis that is more likely to eventually lead to serious liver complications.
Hepatitis B is caused by the spread of the hepatitis B virus from person to person in blood or body fluids. The virus is highly infectious and transmission occurs by various means:
- Infected blood or other body fluids getting into cuts and scratches
- Sexual contact
- Sharing personal items such as toothbrushes and razors
- Sharing of needles by intravenous drug users
- Tattooing, acupuncture and body piercing if equipment is not sterilised
- From a mother to her unborn baby (the highest risk of transmission is during birth).
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.
Acute Hepatitis B symptoms
Some people 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. While acute hepatitis B is usually a mild illness, the type and severity of symptoms experienced differs between individuals and depends on factors such as their age and general health. Symptoms include:
- 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) - 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 is 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 recovery from acute hepatitis B, aperson is immune and is not able to pass the virus on to others.
Chronic Hepatitis B symptoms
Some 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 40% 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 (hepatocellular carcinoma). 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 100 000 chronic hepatitis B sufferers in New Zealand. Maori, Pacific Island peoples and Asians have higher rates of chronic hepatitis B than New Zealanders of European descent.
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.
A FibroScan, which is a type of ultrasound device, may be performed to determine the degree of liver damage. In many cases, a FibroScan avoids the need for a liver biopsy. A biopsy is a surgical procedure that involves taking a small sample of liver tissue for laboratory analysis.
Acute hepatitis B treatment
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 hepatitis B-specific 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 is 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 treatment
The aim of treatment in patients with hepatitis B is to prevent progression to liver cirrhosis, liver failure and liver cancer; and to prevent transmission of the disease to others. 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.
The serious liver complications of chronic hepatitis B can be prevented if the disease is detected and treated in its early stages. Chronic hepatitis B is treated with antiviral medication that reduces the viral load on the body, and allows the immune system to keep infection in check.
The main medications used in the treatment of chronic hepatitis B are:
This medications is a synthetic version of one of the body's natural immune proteins, interferon. It works by assisting the body's immune system to block reproduction of the hepatitis B virus. Pegylated interferon is given as a course of weekly injections over a period of up to 48 weeks. Side effects can be troublesome and include flu-like symptoms such as muscle aches, fatigue and a feeling of being generally unwell.
Entecavir and tenofovir
These medications are anti-viral drugs, which are taken orally every day. They are potent drugs that can reduce the viral load to undetectable levels in the blood in many people with chronic hepatitis B. They are generally well tolerated with few side effects. Tenofovir is the preferred medication for use during pregnancy and breastfeeding when there is a high risk of mother-to-child transmission of the hepatitis B virus.
Liver transplantation may be a treatment option for some patients with liver cancer or liver failure. Hepatitis B-specific immune globulin and antiviral medication is usually used before and after the transplant procedure to prevent recurrence of the hepatitis B virus.
Vaccination and other prevention measures
Vaccination is a safe and effective way of preventing the spread of hepatitis B. Since 1985 the hepatitis B vaccine has been part of the national immunisation schedule, and in 1988 New Zealand was one of the first countries to introduce universal infant hepatitis B immunisation.
The vaccine is given to babies at age six weeks, three months and five months. Babies born to mothers with hepatitis B receive an extra dose of the vaccine at birth as well as a dose of hepatitis B-specific immune globulin.
In children and adolescents who didn't receive the hepatitis B vaccine in the first year of life, the full three-dose course is recommended.
Hepatitis B immunisation is recommended and publicly funded for all infants and children up to their 18th birthday, household and sexual contacts of people with acute or chronic hepatitis B, and various other high-risk populations.
Measures that can help prevent the spread of the hepatitis B virus include:
- Teaching children not to touch the blood or wounds of others
- Covering cuts, scratches and grazes
- Not sharing personal items such as razors and toothbrushes
- Avoiding intravenous drug use
- Practising safe sex, including the use of condoms.
Further support and information
The Hepatitis Foundation can offer support and information on hepatitis B.
The Hepatitis Foundation of New Zealand
Freephone: 0800 33 20 10
For information about hepatitis B vaccination, consult a doctor or contact the:
Immunisation Advisory Centre
Freephone: 0800 466 863
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Last reviewed - August 2017