Hepatitis B

chronic infection in which the patient never gets rid of the virus and many years later develops cirrhosis of the liver or liver cancer. HBV is the most serious type of viral hepatitis and the only type causing chronic hepatitis for which a vaccine is available.

WHO GETS HEPATITIS B?
In much of the developing world, (sub-Saharan Africa, most of Asia, and the Pacific), most people become infected with HBV during childhood, and 8% to 10% of people in the general population become chronically infected. In these regions liver cancer caused by HBV figures among the first three causes death by cancer in men.
High rates of chronic HBV infection are also found in the Amazon and the southern parts of Eastern and Central Europe. In the Middle East and Indian sub-continent, about 5% are chronically infected. Infection is less common in Western Europe and North America, where less than 1% are chronically infected.
Young children who become infected with HBV are the most likely to develop chronic infection. About 90% of infants infected during the first year of life and 30% to 50% of children infected between 1 to 4 years of age develop chronic infection. The risk of death from HBV-related liver cancer or cirrhosis is approximately 25% for persons who become chronically infected during childhood.

HOW DO PEOPLE GET INFECTED ?
Hepatitis B virus is transmitted by contact with blood or body fluids of an infected person in the same way as human immunodeficiency virus (HIV), the virus that causes AIDS. However, HBV is 50 to 100 times more infectious than HIV.
The main ways of getting infected with HBV are:
• Perinatal (from mother to baby at the birth)
• Child-to-child transmission
• Unsafe injections and transfusions
• Sexual contact
Worldwide, most infections occur from infected mother to child, from child to child contact in household settings, and from reuse of unsterilized needles and syringes. In many developing countries, almost all children become infected with the virus.
In many industrialized countries (e.g. Western Europe and North America), the pattern of transmission is different. In these countries, mother-to-infant and child-to-child transmission accounted for up to one third of chronic infections before childhood hepatitis B vaccination programmes were implemented. However, the majority of infections in these countries are acquired during young adulthood by sexual activity, and injecting drug use. In addition, hepatitis B virus is the major infectious occupational hazard of health workers, and most health care workers have received hepatitis B vaccine.
Hepatitis B virus is not spread by contaminated food or water, and cannot be spread casually in the workplace.

CAN CHRONIC HEPATITIS B AND LIVER CANCER BE TREATED?
Liver cancer is almost always fatal, and usually develops between 35 and 65 years of age, when people are maximally productive and with family responsibilities. The loss of a mother or a father in a developing country can devastate the entire family. In developing countries, most people with liver cancer die within months of diagnosis. In industrialized countries, surgery and chemotherapy can prolong life up to a few years. Chronic hepatitis B in some patients is treated with drugs called interferon or lamivudine, which can help some patients. However, interferon or lamivudine therapy costs thousands of dollars and will never be available to most patients in developing countries. Patients with cirrhosis are sometimes given liver transplants, with varying success. It is preferable to prevent this disease with vaccine than to try and cure it.

SYMPTOMS AND COMPLICATIONS
Hepatitis B virus infection may either be acute (self-limited) or chronic (long-standing). Persons with self-limited infection clear the infection spontaneously within weeks to months.
The greater a person's age at the time of infection, the greater the chance their body will clear the infection. More than 95% of people who become infected as adults or older children will stage a full recovery and develop protective immunity to the virus. However, only 5% of new-born that acquire the infection from their mother at birth will clear the infection. Of those infected between the age of one to six, 70% will clear the infection. When the infection is not cleared, one becomes a chronic carrier of the virus.
Acute infection with hepatitis B virus is associated with acute viral hepatitis - an illness that begins with general ill-health, loss of appetite, nausea, vomiting, body aches, mild fever, dark urine, and then progresses to development of jaundice. It has also been noted that itchy skin all over the body, has been an indication as a possible symptom of all hepatitis virus types. The illness lasts for a few weeks and then gradually improves in most of the affected people. A few patients may have more severe liver disease (fulminant hepatic failure), and may die as a result of it. The infection may also be entirely asymptomatic and may go unrecognized.
Chronic infection with hepatitis B virus may be either asymptomatic or may be associated with a chronic inflammation of the liver (chronic hepatitis), leading to cirrhosis over a period of several years. This type of infection dramatically increases the incidence of liver cancer. Hepatitis D infection requires a concomitant infection with hepatitis B. Co-infection with hepatitis D increases the risk of liver cirrhosis and subsequently, liver cancer.