Hepatitis B Virus
What is "hepatitis"?
The medical term "hepatic" relates to the liver and "hepatitis" means "inflammation of the liver". Chronic (long-term) inflammation of the liver can result in liver damage or failure if left untreated. Liver damage can be caused by many different things - drinking too much alcohol, injury, autoimmune disorder, adverse drug reactions, or viruses such as hepatitis B or C. Read more about vital role of the liver.
What is hepatitis B?
Hepatitis B is a virus which is common in New Zealand and which can affect the liver. This virus is widespread throughout Asia and the Western Pacific. Hepatitis B is the most common serious liver infection in the world. It is caused by the hepatitis B virus (HBV), which attacks liver cells. In chronic (long-term) carriers of the virus it can lead to cirrhosis (scarring), liver cancer and liver failure if it is not detected and managed. It is the leading cause of liver cancer in the world. It is estimated that 350 million people worldwide are carriers of the hepatitis B virus. Each year, over one million of these people die from hepatitis B-related liver disease, including cirrhosis and liver cancer.
How is it spread?
Unlike hepatitis A, which is a disease of poor hygiene, hepatitis B is spread mainly by transfer of infected blood and other body fluids from one person to another. The amount required is tiny and we suspect that in the past, before the introduction of vaccination, many infections in New Zealand were due to direct playground contact between children with abrasions and sores, or through grazing on stones and rough surfaces, leaving infection for others to catch in the same way. The virus can also be spread sexually. A mother who is chronically infected with hepatitis B may infect her child during birth. HBV is 100 times more infectious than HIV. Fortunately infection can be prevented through vaccination.
What is a so-called "carrier"?
A carrier is a person who has been infected with the virus, and instead of getting rid of it or becoming ill, carries it in their body as a chronic (long-term) infection (longer than six months). Babies who are infected generally become carriers. Once hepatitis B has taken hold, carriers, particularly children, may spread the infection to other people for many years. Infant immunisation is the key to breaking the cycle of hepatitis B transmission.
The good news is that there is a safe and effective vaccine against the virus. In New Zealand this is on the immunisation schedule for infants and children up to sixteen years, free of charge through general practitioners. The course of vaccine for an infant consists of three doses scheduled for six weeks, three months and five months of age. Mothers who are carriers are identified by a blood test in pregnancy and their babies are offered protection by an injection of immune globulin at birth followed by a course of vaccine. Household contacts and sexual partners of carriers are also offered testing and, if not already infected or immune to the virus, are entitled to free vaccination. Once someone is chronically infected with hepatitis B, it is too late for vaccine to be of help to them. Most carriers were infected as infants or children more than twenty years ago, before the introduction of vaccination.
Hepatitis B vaccination is also recommended but not publicly funded for adults at risk because of their occupation (in some cases employers may fund vaccination). The relevant occupational groups include dentists, medical practitioners, nurses, laboratory technologists, students entering the health professions, orderlies and any other emergency, educational, or health care workers who may come into contact with blood or body fluids in the course of their work.
Other adults at risk include:
- those undergoing renal dialysis
- individuals with haemophilia and other regular recipients of blood products
- persons (staff and patients) in institutions caring for intellectually disabled persons
- prison inmates
- men who have sex with men
- injecting drug users
- persons with a high number of sexual partners
- commercial sex workers
Note: The above recommendations are quoted from the Immunisation Handbook, published by the Ministry of Health. See the Handbook for details on dosage and timing of doses of vaccine, and immune globulin where applicable.
What else can be done to prevent infection with hepatitis B?
All blood used for transfusion in NZ is screened for the hepatitis B virus. If you are a carrier you should not donate blood. You are advised not to share razors, towels or toothbrushes with others. You should cover any open cuts and sores, and wipe up blood spills, cleaning the surface with bleach afterwards. There is no need to avoid normal family interaction (e.g. kissing your children) but your family should be protected by vaccination. Needle sharing by drug users can also transmit hepatitis B and should be avoided.
What about sexual transmission?
Hepatitis B can be transmitted sexually. Sexual transmission is much less likely if condoms are used. In long-term relationships, the partners of carriers should be tested and, if susceptible, vaccinated against hepatitis B. If both partners are carriers, or one is a carrier and the other is immune, there is no need to be concerned about sexual transmission.
What happens after infection with hepatitis B?
There are three different ways in which we may respond to infection with hepatitis B. Most people who are infected get rid of the virus without having a recognised illness and are then immune (i.e. they are protected from further infection). Probably about one-fifth of those infected get the recognisable full-blown illness with jaundice, but then get rid of the virus; this is called acute hepatitis B. About another fifth become chronic "carriers" of the virus, especially if they are infected in early life (usually in the first five years). About 1% of those chronically infected lose the virus naturally each year. People first exposed to hepatitis B as adults very seldom become chronic carriers.
Do people carrying a chronic infection become ill?
People who are chronic carriers do not get ill when they are infected, or for many years afterwards. Most will probably never suffer from the effects of the virus. However, some chronically infected people do develop more serious liver disease, usually as adults, with development of liver scarring (cirrhosis) that can lead to liver failure. They may also develop liver cancer. Doctors estimate between one in six and one in ten male carriers may get liver cancer, which is less common in females. Some families are particularly prone to liver cancer.
How do I know if I might be chronically infected?
Only a blood test can tell this - the Hepatitis Foundation can organise this for you.
If I am a chronically infected, what can I do to prevent serious disease?
The first thing you can do is to get a regular blood test to check if the virus is affecting your liver (usually six-monthly, if all is going well). More information on the blood tests.
The Hepatitis Foundation will put you on its follow-up register, if you request it, and send reminders for these tests and tell you if they are showing any problem. If your liver function becomes abnormal for a long period (several years) you may be at risk of liver scarring, and there are now some treatments available through specialists for this. A blood test will also check for a protein which gives early warning of liver cancer (in some high risk cases regular liver ultrasound scans are also recommended). Where abnormal blood test results are persistent, further diagnosis may be carried out, including ultrasound examination and liver biopsy.
What treatments are available for patients chronically infected with hepatitis B?
A successful treatment is one where the virus ceases to multiply and the liver function returns to normal, though usually the patient remains chronically infected.
Pegylated Interferon treatment is a synthetic form of a natural product that is usually produced during virus infections. It attacks the virus directly, and indirectly by stimulating the immune system. Unfortunately it has a number of drawbacks - it is given by weekly injection, it only works in a proportion of cases (1/3 to 2/3 according to selection criteria), and it causes side effects in everyone. Most troublesome are muscle aches and malaise, though these often improve after the first few doses, and can be lessened by giving the dose at night with aspirin or paracetamol. It can also aggravate depressive symptoms and affect the blood count, which needs regular review. It has the advantage of only requiring one year of treatment in total.
Entecavir (Baraclude) and Lamivudine (ZeffixTM)
Entecavir (Baraclude) and Lamivudine (ZeffixTM) are available as a tablet, and are well tolerated. They work by stopping the hepatitis B virus replicating, and in most cases stop further liver damage while treatment continues. In some cases treatment can be stopped but in many needs to be continued indefinitely. The virus may develop resistance to Lamivudine (ZeffixTM) - up to 65 % after three years - but this is much less of a problem with Entecavir (Baraclude) 1% at year six. You can find more information about at www.medsafe.govt.nz
For HBV carriers with serious liver disease that has become resistant to lamivudine this drug is an alternative. Like lamivudine it is well tolerated and suppresses HBV but often needs to be taken long-term.
Tenofovir is another very powerful antiviral that has a low rate of viral resistance.
Regular blood testing can detect the early signs of liver cancer when tumours are still small enough to be removed by surgery. This procedure is called liver resection. For some carriers, a liver transplant is a better option.
Where can I go for further information and support?
For more information contact us.