Hepatitis B

Hepatitis B

What is Hepatitis B virus?

Hepatitis B virus is a disease of the Liver. Hepatitis refers to any condition causing inflammation of the liver. Although many Hepatitis B viruses can cause inflammation of the liver, Hepatitis B is one of six viruses that specifically target the liver – which is why they are called Hepatitis viruses. The Hepatitis B viral particle is made up of an outer surface coat – hep B surface antigen (HBs), inner core ds DNA (hep b core antigen – HBc), and hep e antigen (HBe). These parts of the Hepatitis B virus particle and the antibodies produced against them by the body are used for laboratory detection of the virus.

Statistics on Hepatitis B virus

Hep B is prevalent world-wide and has infected more than 2000 million people, with about 300 million carriers. The disease is more common in South-East asia and Africa. While the rate of carriage of Hepatitis B is 0.1% in the UK, it is as high as 20% in some areas of Asia and Africa. In those areas Hepatitis B carriage is perpetuated by spread from mother to baby during birth.

Risk Factors for Hepatitis B virus

The Hepatitis B virus is found in body secretions.

  • Hepatitis B can be spread intravenously (e.g. by transfusion of infected blood, blood products, or by contaminated needle used by drug addicts, tattooists or acupuncturists)
  • By close personal contact (e.g. in unprotected sexual intercourse).
  • The Hepatitis B virus can also be transmitted from mother to child during parturition or soon after birth.

Progression of Hepatitis B virus

  • The incubation period of infectious Hepatitis B can be as long as 2-3 months.
  • Acute hepatitis can then develop. This can be severe – causing massive liver necrosis (death of liver cells).
  • Around 95% of patients will then recover completely, however 5-10% will develop chronic carriage – where they do not complete control the infection and the virus continues to replicate in liver cells.
  • This can be symptomless, or lead to chronic active hepatitis in 3% overall- continuing liver inflammation which can lead to progressive liver failure. Hepatitis D (delta agent) can contribute to the development of this.
  • Hepatitis B is also an important risk factor for liver cancer – hepatocellular carcinoma, especially in areas such as Asia and Africa where the infection is acquired often at a young age.

How is Hepatitis B virus Diagnosed?

  • Hepatitis B surface antigen detected.
  • Hepatitis B core antibody detected 1-2 weeks after first detection of surface antigen.
  • Hepatitis B surface antibody.
  • Both hepatitis B surface antibody and core antibody persist indefinitely in the blood of patients who have recovered from hepatitis B.
  • Your liver enzyme blood levels may be elevated due to sustained liver damage.

Prognosis of Hepatitis B virus

  • 95% of adults recover completely from Hepatitis B. 1-10% will develop chronic disease.
  • In areas of high endemicity, 80% will become chronic carriers.10-30% of those who develop chronic infection develop chronic liver disease.
  • One percent of Hepatitis B patients proceed to acute fulminant liver failure. Hepatitis B is the most important cause of fulminant hepatitis worldwide. Even with the improved survival of liver transplantation, mortality exceeds 60%.

Hepatitis B virus Prevention

  • Avoid risk behaviours
  • Hepatitis B Vaccination – recommended for those at risk – homosexuals, healthcare workers, those travelling to high risk areas, drug abusers and haemodialysis patients
  • Post-exposure for non-immunised individuals: (sexual partners, needle stick injury, infants of mothers who are Hepatitis B Ag positive)
  • Hepatitis B Immunization plus specific antihepatitis immunoglobulin

How is Hepatitis B virus Treated?

Treatment of the infected patient:

  • Supportive, avoid alcohol.
  • Interferon alpha – administered 3 times a week by the patient (subcutaneously) for 4-6 months. Stimulates immune system to clear virus (clear HBe Ag and HBV DNA). Achieved in approximately 50% of cases.
  • Other antivirals – lamivudine and famciclovir.

More information

Sexually transmitted infections (STIs)
For more information on different types of sexually transmitted infections, prevention of STIs, treatments and effects on fertility, see Sexually transmitted infections (STIs).

Hepatitis B virus References

  1. Kumar P, Clark M. CLINICAL MEDICINE. WB Saunders 2002.
  2. Longmore M, Wilkinson I, Torok E. OXFORD HANDBOOK OF CLINICAL MEDICINE. Oxford Universtiy Press. 2001.
  3. McLatchie G and Leaper DJ (editors). Oxford Handbook of Clinical Surgery 2nd Edition. Oxford University Press 2002.
  4. Raftery AT Churchill’s pocketbook of Surgery. Churchill Livingsone 2001.
  5. Timbury, MC. Notes on Medical Virology, 11th Ed.

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