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Hepatitis B

  • Hepatitis B is a viral infection that attacks the liver and can cause both acute and chronic disease.

  • The virus is transmitted through contact with the blood or other body fluids of an infected person.
  • An estimated 257 million people are living with hepatitis B virus infection (defined as hepatitis B surface antigen positive).
  • In 2015, hepatitis B resulted in 887 000 deaths, mostly from complications (including cirrhosis and hepatocellular carcinoma).
  • Hepatitis B is an important occupational hazard for health workers.
  • However, it can be prevented by the currently available safe and effective vaccine.
  • Hepatitis B is a potentially life-threatening liver infection caused by the hepatitis B virus (HBV). It is a major global health problem.
  • It can cause chronic infection and puts people at high risk of death from cirrhosis and liver cancer.
  • A vaccine against hepatitis B has been available since 1982.
  • The vaccine is 95% effective in preventing infection and the development of chronic disease and liver cancer due to hepatitis B.

TRANSMISSION

  • The hepatitis B virus can survive outside the body for at least 7 days.
  • During this time, the virus can still cause infection if it enters the body of a person who is not protected by the vaccine.
  • The incubation period of the hepatitis B virus is 75 days on average but can vary from 30 to 180 days.
  • The virus may be detected within 30 to 60 days after infection and can persist and develop into chronic hepatitis B.
  • Hepatitis B is also spread by percutaneous or mucosal exposure to infected blood and various body fluids, as well as through saliva, menstrual, vaginal, and seminal fluids.
  • Sexual transmission of hepatitis B may occur, particularly in unvaccinated men who have sex with men and heterosexual persons with multiple sex partners or contact with sex workers
  • Mother to the child at birth (perinatal transmission).

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.
  • A small subset of persons with acute hepatitis can develop acute liver failure, which can lead to death.
  • In some people, the hepatitis B virus can also cause a chronic liver infection that can later develop into cirrhosis (a scarring of the liver) or liver cancer.

WHO IS AT RISK FOR CHRONIC DISEASE?

  • The likelihood that infection becomes chronic depends upon the age at which a person becomes infected.
  • Children less than 6 years of age who become infected with the hepatitis B virus are the most likely to develop chronic infections.

IN INFANTS AND CHILDREN:

  • 80–90% of infants infected during the first year of life develop chronic infections; and
  • 30–50% of children infected before the age of 6 years develop chronic infections

  IN ADULTS:

  • less than 5% of otherwise healthy persons who are infected as adults will develop chronic infection; and
  • 20–30% of adults who are chronically infected will develop cirrhosis and/or liver cancer.

HBV-HIV CO-INFECTION

  • About 1% of persons living with HBV infection (2.7 million people) are also infected with HIV.
  • Conversely, the global prevalence of HBV infection in HIV-infected persons is 7.4%.
  • Since 2015, WHO has recommended treatment for everyone diagnosed with HIV infection, regardless of the stage of the disease.
  • Tenofovir, which is included in the treatment combinations recommended in the first intention against HIV infection, is also active against HBV.

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