What is Hepatitis B?

Hepatitis B is an infection caused by a virus. It causes inflammation of the liver. The liver is responsible for detoxifying many drugs and toxins, helping with the absorption of certain foods, producing substances that control bleeding and fight infections and storing energy for future use. When the liver is inflamed or damaged, these processes slow down or stop.

Hepatitis B has two phases – acute (or short-term) hepatitis B and chronic (or long-term) hepatitis B. Acute hepatitis B may not even be recognized, but may be thought to be a case of the flu. The symptoms develop within 30 to 180 days of exposure to the virus and include loss of appetite, fatigue, low-grade fever, muscle and joint aches, nausea and vomiting, yellow skin, dark urine, itching all over the body and pain over the liver (under the right-sided lower rib cage). The treatment of acute hepatitis B is no more complicated than monitoring the liver function via blood tests. In very rare occasions (less than one percent), complete liver failure may occur, and in some cases a liver transplant may be needed.

Patients with acute hepatitis B usually recover completely within six weeks. The conversion rate from acute to chronic hepatitis B is largely determined by the age of the patient when they develop acute hepatitis B. For example, infants who contract the acute disease from their mothers before being born have a 95 percent chance of developing chronic hepatitis B, while only five percent of adults with acute hepatitis B go on to develop chronic hepatitis B. There is no medical treatment to prevent conversion of acute hepatitis B to the chronic form. Chronic hepatitis lasts six months or longer and develops when the liver cannot recover from acute hepatitis B. Many people with chronic hepatitis B (30 to 50 percent) do not even remember having the symptoms characteristic of acute hepatitis B.

Many people with chronic hepatitis B have no symptoms and are only recognized when their doctor does routine blood work. They may develop vague symptoms such as fatigue. During a physical exam, they may appear completely normal or they may show signs of chronic liver disease – for example, jaundice (yellow skin), enlarged spleen, swollen legs and confusion. Over a span of time ranging from months to years, about 12 to 20 percent of patients develop cirrhosis; a state in which healthy liver tissue becomes replaced by scar tissue. A very small number of people with cirrhosis go on to develop hepatocellular carcinoma. In other words, most people with chronic hepatitis B live out their lives as a chronic asymptomatic carrier – that is, they can pass hepatitis B on to other people but they do not have any symptoms themselves. In the United States, one to two percent of all people are asymptomatic carriers of hepatitis B.

Antiviral medications are available for treatment of chronic hepatitis B. Treatment may last more than a year, depending on the severity of the illness and the body’s response to treatment. Treatment may involve many side effects and does not work for everybody. People who have progressed to severe cirrhosis may need to consider liver transplant, but this is a very unusual circumstance.

In the United States, hepatitis B is passed between individuals by mother to infant transmission or through transfusions, sexual transmission, needles shared by intravenous drug users or by transmission in the health care setting, largely via accidental needle sticks or contaminated instruments.

People who are at risk for hepatitis B infection should be vaccinated against the disease. The following groups (among others) are recommended to receive the vaccine: all children less than 18 years old; all health care and public safety workers; travelers to countries where hepatitis B is common; prisoners; intravenous drug users; people with multiple sex partners; and people with other chronic liver diseases. The vaccine is given over a several month period in three parts.