Hepatitis B is a virus (HBV) that causes an inflammation of the liver. Severe outcomes may be observed following acute hepatitis, but they mainly result from the complications of chronic HBV infection (e.g., liver cirrhosis and cancer).
Symptoms of hepatitis B
After an incubation period of three to four months, acute hepatitis B is usually associated with a loss of appetite, weakness, nausea, abdominal pain, jaundice, skin rash, and joint pain that last several weeks.
1 to 2% of subjects develop fulminant hepatitis B, a total acute necrosis of the liver, for which mortality rate is extremely high. (7-8)
Following HBV infection, 10% of patients will develop chronic hepatitis (i.e., persistence of HBV in the body) with the potential risk to develop cirrhosis and liver cancer. (8)
The risk of transition to a chronic state is particularly frequent among immunodepressed individuals and newborns.
Epidemiology and vaccination against hepatitis B
HBV is transmitted primarily through blood, and to a lesser extent by other body fluids.
WHO estimates that about two billion people worldwide have been infected with the virus. An estimated 600,000 persons die each year due to the acute or chronic consequences of hepatitis B.
7 - Hepatitis B immunization. Introduction hepatitis B into childhood immunization services. Geneva, 2001 (WHO/V&B/01.31;
Hepatitis B WHO Factsheet N°204 revised August 2008
8 - Hepatitis B. Epidemiology and Prevention of Vaccine-Preventable Diseases. The Pink Book 9th ed. CDC; 2006. p. 207-31.