Hepatitis B

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Hepatitis B is a potentially life-threatening liver infection caused by the hepatitis B virus. It is a major global health problem. It can cause chronic liver disease and chronic infection and puts people at high risk of death from cirrhosis of the liver and liver cancer.

Hepatitis B is a potentially life-threatening liver infection caused by the hepatitis B virus. It is a major global health problem. It can cause chronic liver disease and chronic infection and puts people at high risk of death from cirrhosis of the liver and liver cancer.

More than 240 million people have chronic (long-term) liver infections. About 600 000 people die every year due to the acute or chronic consequences of hepatitis B.

Transmission

In highly endemic areas, HBV is most commonly spread from mother to child at birth, or from person to person in early childhood.

Perinatal or early childhood transmission may also account for more than one third of chronic infections in areas of low endemicity, although in those settings, sexual transmission and the use of contaminated needles, especially among injecting drug users, are the major routes of infection.

Symptoms

Most people do not experience any symptoms during the acute infection phase. However, some people have acute illness with symptoms that last several weeks, including yellowing of the skin and eyes (jaundice), dark urine, extreme fatigue, nausea, vomiting and abdominal pain.

In some people, the hepatitis B virus can also cause a chronic liver infection that can later develop into cirrhosis of the liver or liver cancer.

Diagnosis

Laboratory diagnosis of hepatitis B infection centres on the detection of the hepatitis B surface antigen HBsAg. WHO recommends that all blood donations are tested for this marker to avoid transmission to recipients.

• Acute HBV infection is characterized by the presence of HBsAg and immunoglobulin M (IgM) antibody to the core antigen, HBcAg. During the initial phase of infection, patients are also seropositive for HBeAg.
• Chronic infection is characterized by the persistence (>6 months) of HBsAg (with or without concurrent HBeAg). Persistence of HBsAg is the principal marker of risk for developing chronic liver disease and hepatocellullar carcinoma (HCC) later in life.

The presence of HBeAg indicates that the blood and body fluids of the infected individual are highly contagious

Treatment

Some people with chronic hepatitis B can be treated with drugs, including interferon and antiviral agents. Treatment can slow the progression of cirrhosis, reduce incidence of HCC and improve long term survival.