Vaccine-preventable diseases
Hepatitis B |
What is it?
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
After an incubation period of 3 to 4 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
HBV is transmitted primarily through blood, and to a lesser extent by other body fluids.
Each year, over 250,000 people die from acute or chronic diseases associated with HBV. Hepatitis B vaccines have been available since the beginning of the 1980s, and many countries have introduced hepatitis B vaccine into their immunization program.
References:
7 - Hepatitis B immunization. Introduction hepatitis B into childhood immunization services. Geneva, 2001 (WHO/V&B/01.31;
www.who.int/vaccines-documents).
8 - Hepatitis B. Epidemiology and Prevention of Vaccine-Preventable Diseases. The Pink Book 9th ed. CDC; 2006. p. 207-31.
