Dr. Widjaja Luman
Consultant Gastroenterologist and General Physician
B Sc (St. Andrews), MB ChB (Man), MRCP (UK), M.D. (Edin),
CCST (UK), FRCP (Edin)
(Ahli penyakit pencernaan dan hepar)
Hepatitis B is a virus which infects liver cells and can cause inflammation of the liver in both acute and chronic forms. It is present worldwide and studies have shown that in some countries in Asia and Africa, up to 10% of the population are carriers. WHO (World Heath Organisation) estimates that in 2015, 257 million people have chronic hepatitis B infection. About 3.6 per cent of the population aged 18-79 in Singapore, or about 150,000 people, are hepatitis B carriers. However, many are unaware of their condition and the condition is often undiagnosed until patients develop symptoms of advanced liver disease.
How do people get infected?
Hepatitis B virus is carried in the blood, so it can only be acquired by blood to blood contact (parenteral route). Hepatitis B can be transmitted by the following ways:
Vertical transmission from Mother to Baby
The virus is passed from mothers who are carriers to their newborns at the time of birth. This is the most common mode of transmission worldwide before the adoption of wide spread hepatitis B vaccination at birth. Newborns are not symptomatic or become unwell with the infection but over 90% end up as carriers with chronic hepatitis B. Many people with chronic hepatitis B remain well but some will go on to develop serious liver problems such as cirrhosis and liver cancer. These carriers of chronic hepatitis are infectious to their close contacts.
Horizontal transmission between two adults
The virus is passed from one infected adult to another through blood to blood contact in the following ways:
- Unprotected sexual contact with infected persons. This can occur between heterosexual and homosexual partners.
- Blood Transfusion. All blood products are routinely screened for hepatitis B (and other pathogens) so this is a very rare occurrence now.
- Needle sharing of contaminated needles among intravenous drug users. Or contaminated needles during tattoo, acupuncture or ear piercing.
Unlike the newborn in vertical transmission, infected adults become ill with the infection (acute hepatitis) but majority (over 90%) have full recovery. Less than 10% become carriers.
What are the symptoms and course of disease?
Newly infected adults usually become symptomatic 4 to 6 weeks after acquiring the infection and develop acute hepatitis with fever, lethargy, nausea, vomiting, muscle ache and jaundice (yellowing of the skin). A small subset of persons with acute hepatitis can develop acute liver failure, which can lead to death. The illness can last for several weeks. Immune system will clear the virus and over 90% of individuals are expected to have full recovery within 6 months. These individuals are no more infectious. However, 10% of infected individuals will recover from their illness but remain as chronic hepatitis B carriers. These carriers remain infectious to others.
Many hepatitis B carriers (also known as chronic hepatitis B) do not feel unwell and become aware that they are carriers only through routine screening. These are usually individuals who were infected by vertical transmission at birth or infected adults who have recovered from acute infection. It is important for these carriers to know whether they are viraemic (carriers with active viral replication) or non viraemic carriers (no active viral replication). All chronic hepatitis B carriers have the long term risk of cirrhosis and liver cancer. Cirrhosis is like a scarring of the liver, which can cause serious problems and liver failure when it is severe. Cirrhosis usually takes many years to develop after a person has been infected with hepatitis B. The risk of cirrhosis and liver cancer is higher in the viraemic carriers. Therefore treatment should be considered for these individuals.
What are the tests?
A simple blood test can detect if you are infected with the hepatitis B. HBsAg is the test that detects the surface protein on the virus. If HBsAg is positive, it means that the person is a chronic hepatitis B carrier. If your HBsAg test is positive, then other tests may be advised to check on the multiplicative state of the virus (viraemic state), to assess the severity of liver inflammation, and how well your liver works. There are blood tests that detect various parts of the genetic sequence of the virus (HBV DNA) and determining the concentration of these DNA sequences gives result of the viral count or viral load in the blood. The HBV DNA count determines the viraemic (multiplicative) state. Blood test called liver function test can determine the degree of liver inflammation. Ultrasound scan of the liver will show presence of cirrhosis and tumour in liver. Ultrasound scan is similar to the scan performed for pregnant women. Your doctor may order Transient elastography or magnetic resonance elastography. These two tests are for determining stiffness of liver, or degree of fibrosis and scarring.
Occasionally your doctor may also order liver biopsy. This involves taking a small core of your liver through the skin on the upper right side of your abdomen with a special needle. It is performed after you have had injection of local anaesthetic to make the area numb. This test will allow your doctor to determine severity of inflammation and scarring caused by the virus before starting therapy. It is seldom performed nowadays.
Can hepatitis B infection be prevented?
In countries with high prevalence of hepatitis B (most countries in Asia), it is mandatory that all newborns are vaccinated at birth. Booster may be required later in adulthood. Non immune individuals can be vaccinated during adulthood if they have not received vaccination at birth. Vaccination is mandatory for individuals working in high risk areas such as healthcare. Partners or household members of infected persons should be vaccinated as well in order to prevent cross household infection.
For infected mothers (carriers) with high viral count (high HBV DNA), it is advisable for the mothers to be treated during the third trimester with anti viral drugs so that the viral count can be brought down. The higher the mother’s HBV DNA count (>1 000,000 copies/ml), the higher the risk of passing the virus to the newborn baby. This measure is in addition to vaccinating newborns at birth. This combined approach has been shown to prevent newborns from getting infected at birth even from mothers with high viral count.
Can I get pregnant?
Pregnancy is not contraindicated in Hepatitis B carriers. The risk of vertical transmission to new born baby depends on the maternal viraemic level. For mothers with high viral count (above 1 million copies/ml), anti viral therapy could be prescribed during the third trimester in order to bring down the viraemic level at the time of birth thereby reducing the risk of vertical transmission to the newborn. The newborn should be vaccinated at birth too. The child should be tested for hepatitis B antigen (HBsAg) and antibodies against hepatitis B at 1 year of age.
What are the treatments?
For acute infection, most infected adults recover fully after experiencing a short, mild, flu-like illness. Occasionally the acute infection can progress to severe liver dysfunction with jaundice and liver failure. Anti viral therapy is prescribed in acute illness as it can bring more rapid recovery and prevent progression to liver failure.
90% of adults who are infected with hepatitis B recover fully and are never troubled by the virus again. Only about 10% go on to be ‘chronic carriers’. However, the situation is different for babies infected at birth, because about 90% of them go on to become chronic carriers. This chronic infection can continue for many years, and may lead to more serious complications. These include scarring of the liver (cirrhosis) which is seen in 20% of people with chronic hepatitis and this complication often takes 10-30 years to develop.
Cirrhosis can lead to problems such as confusion (hepatic encephalopathy), swelling in tummy (ascites) and ankle (oedema) with water retention, bleeding of veins from oesophagus (oesophageal varices) and liver cancer (hepatoma). Once cirrhosis has developed, it cannot reverse back to normal again, even if the liver inflammation which caused it improves. Doctors prefer to give treatment early to try and prevent the development of cirrhosis.
For chronic hepatitis B carriers, non drug therapy is as important as anti viral therapy. It would be advisable to limit yourself to occasional alcohol intake. Cirrhosis is more likely to develop in moderately heavy drinkers who are infected with hepatitis B. Healthy diet and regular exercise to prevent obesity and Non alcocholic fatty liver disease (NAFLD) is important. Hepatitis B carriers with superimposed NAFLD have more rapid progression to cirrhosis and liver cancer.
Chronic hepatitis B carriers should be under regular follow up for surveillance of cirrhosis and liver cancer. This should be done at frequency of at least annually, preferably at 6 monthly interval. The rationale for surveillance is because a large number of liver cancer are diagnosed at a late stage, when the patient has only a few months left to live. Aim of surveillance is to detect liver cancer at early stage when it is amenable for curative therapy by surgical resection or local ablation.
Unfortunately we still do not have treatment that can clear the virus from the body for those with chronic hepatitis B carriers. All the available treatment now only works by suppressing viral replication. Treatment for hepatitis B does not cure hepatitis B but works to delay or even to prevent complications from developing, like liver damage and ‘scarring’ of the liver (cirrhosis). People with chronic hepatitis B usually need treatment to stop or to reduce the activity of the virus, so limiting liver damage. A liver specialist will usually advise on when treatment may be beneficial. Non viraemic carriers do not need treatment. Treatment is indicated only for viraemic carriers if they have evidence of liver inflammation and severe scarring on blood test or ultrasound scan. Carriers should discuss with their doctors the indication for treatment.
There are two types of treatment currently given :
- Interferon which works by boosting your immune system to clear the virus. It is given by subcutaneous injection once per week for one year. The technique used is the same as for injections used to treat diabetes. It is seldom prescribed nowadays due to its side effects such as lethargy, nausea and fever.
- Antiviral medicines. These work by stopping the hepatitis B virus from multiplying in the body. They include lamivudine, adefovir, tenofovir, and entecavir. Lamivudine and adefovir are seldom prescribed due to high resistance rate after few years of therapy. Tenofovir and entecavir are the drugs commonly prescribed for hepatitis B carriers nowadays. Your doctor will discuss these in more detail with you. In general, treatment is long term as it works only to suppress the viral replication thereby reducing liver inflammation and slowing down progression to liver cirrhosis. Relapse of viral replication occurs frequently when the medication is discontinued.
For patients who have developed complications of cirrhosis mentioned above, your doctor may recommend that you be considered for liver transplant.
The treatment of hepatitis B is a rapidly developing area of medicine. Hopefully more effective medicine will be available soon.