WHO home
All WHO This site only

Immunization, Vaccines and Biologicals

  WHO > Programmes and projects > Immunization, Vaccines and Biologicals > IVB topics
printable version

Hepatitis B: Previous page | 1,2,3,4

Hepatitis B - The disease

  Table of contents for Hepatitis B

What is hepatitis B?

Hepatitis B is caused by a virus that affects the liver. Adults who get hepatitis B usually recover. However most infants infected at birth become chronic carriers i.e. they carry the virus for many years and can spread the infection to others. In 2000, there were an estimated 5.7 million cases of acute hepatitis B infection and more than 521 000 deaths from hepatitis B-related disease.

How is hepatitis B spread?

The hepatitis B virus is carried in the blood and other body fluids. It is usually spread by contact with blood in the following ways:

  • Through an unsafe injection or needle stick. Unsterilized needles or syringes can contain hepatitis B virus from an infected person, for example from a patient or a needle user.
  • Transmission of the virus by mothers to their babies during the birth process, when contact with blood always occurs.
  • Transmission between children during social contact through cuts, scrapes, bites, and scratches.
  • Transmission during sexual intercourse through contact with blood or other body fluids

What are the signs and symptoms of hepatitis B?

The incubation period averages six weeks but may be as long as six months. Infection in young children usually is asymptomatic. However, a larger proportion of children may become chronic carriers compared to adults. People who do show symptoms may feel weak and may experience stomach upsets and other flu-like symptoms. They may also have very dark urine or very pale stools. Jaundice is common (yellow skin or a yellow colour in the whites of the eyes). The symptoms may last several weeks or months. A laboratory blood test is required for confirmation. Most acute infections in adults are followed by complete recovery. However, many children become chronic carriers. People who recover from acute hepatitis B (and who do not become chronic carriers) are protected from becoming infected again throughout their lives.

What are the complications of hepatitis B?

A small portion of acute infections can be severe and lead to death. The most serious complications, including chronic hepatitis, cirrhosis, liver failure, and liver cancer, occur in people with chronic infection.

What is the treatment for hepatitis B?

There is no treatment for the acute condition. Supportive treatment is indicated. In chronic infection the disease can sometimes be stopped with medications

How is hepatitis B prevented?

It is recommended that all infants receive three doses of hepatitis B vaccine during the first year of life. More recently, some countries have been using a combination vaccine that includes vaccines for diphtheria, tetanus, pertussis, hepatitis B (HepB), and sometimes Haemophilus inflenzae type b (Hib). Programmatically, it is usually easiest if the three doses of hepatitis B vaccine are given at the same time as the three doses of DTP. In countries where hepatitis B is highly endemic, where feasible, a birth dose of HepB is included in the schedule to prevent perinatal hepatitis B infection.

Some countries also recommend immunizing adolescents, health workers and other risk groups

Hepatitis B: 1,2,3,4 | Next page

[an error occurred while processing this directive]