Decoding Hepatitis A common namesake notwithstanding, hepatitis A and B are as different as apples and oranges By Eleanor Yap Hepatitis A and B are two very different infections and often misunderstood by the public. Even though both have similar symptoms, the viruses are quite different. The A variety is food-borne and is not followed by chronic (long-term) problems, while the B kind is spread through sex and blood. Symptoms appear later than A and can eventually cause chronic, serious liver diseases, explains Dr Richard Guan, consultant gastroenterologist, hepatologist and physician at Medical Clinic One at Mount Elizabeth Medical Centre.   The A kind Hepatitis A is a viral infection that causes the liver to get enlarged, inflamed and tender. There is no chronic infection. The virus is excreted in faeces and transmitted through contaminated food and water. The disease is normally contracted through eating shellfish from sewage-contaminated water. It can also be acquired by close contact with individuals infected with the virus.   According to the Singapore National Environment Agency, less than half of the population has immunity against hepatitis A. In children and youths below 25 years of age, only 2% to 7% are immune.   Symptoms appear two to three weeks after the person has been infected. Symptoms during the first week include jaundice, fatigue, fever, loss of appetite, nausea and vomiting, and dark urine.   The best protection is getting a hepatitis A vaccination. Immune globulin can be given for short-term protection and is usually given before and within two weeks after coming in contact with the hepatitis A virus. The vaccine is recommended for travellers to developing countries and people with chronic liver disease.   To prevent hepatitis A, hygiene is critical. Always wash your hands with soap and water after using the toilet, as well as before preparing and eating food.    The B variety Hepatitis B virus (HBV) on the other hand can cause a more severe disease. It is one of the most infectious viruses common in Asia. It is transmitted from mother to child during birth. It can also be transmitted through sharing needles or by any behaviour in which a person’s mucus membranes are exposed to an infected person’s blood, semen, vaginal secretions or saliva.   While the initial sickness is rarely fatal, up to 90% of children infected at birth and about 5% of adults who get hepatitis B are infected for life and run a high risk of developing serious, long-term liver diseases such as cirrhosis (serious scarring of the liver) or liver cancer, which can cause serious complications or death. Most chronic infections are acquired early in life (either perinatally from mother to foetus or during the first year of life), explains Dr Guan. It is very important that chronically infected individuals get themselves screened every six months for signs of liver disease arising from HBV.   Symptoms of acute infection are similar to that of hepatitis A and can include general malaise and low-grade fever. Most chronic hepatitis B sufferers have no symptoms but can spread the virus to others. Treatment is only recommended for those with active viral replication and active liver disease. Drugs approved by the US Food and Drug Administration (FDA) for chronic HBV infection include interferon, lamivudine, adefovir and more recently, entecavir. Another drug, thymosin alpha-1, has been approved in countries outside the US and may have response rates similar to that of interferon. Studies are ongoing in the US to gain FDA approval.   According to the Health Promotion Board, 4% of the population in Singapore has chronic hepatitis B infection. To protect yourself against HBV, avoid high-risk activities such as sexual contact with an infected person and the use of contaminated skin-piercing instruments such as in-body piercing, tattooing and the sharing of injection needles. Wear a condom when having sex and don’t share razors or toothbrushes.   Hepatitis B is a preventable disease. If you are at risk, get vaccinated. A Hepatitis B vaccination is administered in a series of three injections over a six-month period. Approximately 95% of persons who receive the three injections obtain full immunity after receiving the vaccine.   What about C? Hepatitis C virus is another blood-borne virus that can cause chronic liver disease. It is transmitted in the same way as hepatitis B, so avoid infection by exercising the same precautions. Fortunately, with this type of hepatitis in Singapore, the incidence is less than 1%.