Hepatitis B is a disease of the liver caused by a virus (specifically, the
hepatitis B virus). Most people who get it can get rid of the virus on their own, but others can develop chronic (or life-long) hepatitis B.
The cause of hepatitis B is an infection with the hepatitis B virus. This is a DNA virus that belongs to the genus Orthohepadnavirus of the Hepadnaviridae family.
Acute Versus Chronic Hepatitis B
There are two types of hepatitis B -- acute (recently acquired) and chronic (life-long).
For most people with acute hepatitis B, symptoms gradually get better within a couple of months. These people with have no long-lasting liver damage and will recover completely.
For some people, the body is not able to completely get rid of the virus. These people end up having a long-term liver infection. This is called chronic hepatitis B. People with the chronic type can infect others and are at an increased risk of serious liver disease, including
cirrhosis and
liver cancer. In the United States, an estimated 1.25 million people are chronically infected with HBV.
The virus is spread through infected bodily fluids. Among the bodily fluids that can transmit the
hepatitis B virus are infected blood and blood products. It is also spread through contact with other infected bodily fluids, such as semen, vaginal fluids, or saliva.
Casual contact, as in the usual office, factory, or school setting, does not spread the virus. A person cannot get it from a kiss or other normal everyday activities, such as hugging or shaking hands.
Who's at Risk for Hepatitis B?
Some of the people who are at risk of developing hepatitis B include:
- Those who have sex with an infected person
- Men who have sex with men
- Intravenous drug users
- Children of immigrants from disease-endemic areas
- Infants born to infected mothers
- People who live with an infected person
- Healthcare workers
- Hemodialysis patients
- People who received a transfusion of blood or blood products before July 1992
- People who received clotting factors made before 1987
- International travelers.
Following transmission of the virus, a person does not immediately become sick. Once the virus enters the body, it travels to the liver, where it begins to multiply.
After 30 to 180 days, symptoms can begin. This period between hepatitis B transmission and the start of signs and symptoms is called the "hepatitis B incubation period."
Many people who get hepatitis B will not have any symptoms. This is especially true of children. If people do have symptoms, they may start abruptly and include the following:
- Yellowing of the skin or eyes (also known as jaundice)
- Feeling very tired
- Abdominal pain (or stomach pain)
- Not feeling very hungry
- Dark urine
- Nausea
- Diarrhea
- Muscle pain
- Joint pain
- A low-grade fever.
In a number of people, these symptoms may be confused with
stomach flu symptoms, especially in the early stages of the illness.
(Click Hepatitis B Symptoms for more information on the possible impact of an infection with this virus.)
A person is contagious during the
hepatitis B incubation period. A person who is infected with the virus begins to be contagious early in the incubation period. About one-half of people remain contagious for up to two months after symptoms begin. The remainder of people who do not develop chronic hepatitis B will remain contagious for up to 15 weeks after symptoms begin. If a person develops the chronic form of the infection, they will remain contagious indefinitely.
In order to make a diagnosis, the doctor will ask the patient a number of questions and perform a physical exam to look for signs and symptoms of hepatitis B.
If the doctor suspects hepatitis B, he or she will order certain tests to help diagnose the disease. Some of these tests will look for high levels of liver enzymes. Other tests will look for antibodies the body has made against the virus.
Treatment for Hepatitis B
There are no specific medicines that can cure acute hepatitis B
(see Cure for Hepatitis B). Therefore, treatment for the acute type is focused on dealing with any symptoms or complications that may occur. This is known as supportive care. Even without specialized treatment for acute hepatitis B, most people recover completely within a few months.
For people with chronic hepatitis B, specific medicines are available to help slow down liver damage and possibly prevent complications. Some of these medications include:
- Alpha interferon
- Pegylated alpha interferon
- Lamivudine (Epivir-HBV®)
- Adeforvir dipivoxil (Hepsera®)
- Entecavir (Baraclude®)
- Telbivudine (Tyzeka®).
However, medicines are not right for everyone with chronic hepatitis B.
While there is no cure, most people infected with the virus get well without any long-term problems.
Chronic infection with HBV means that you have a long-term HBV infection; your body did not get rid of the virus when you were first infected with HBV. The risk of progressing to chronic hepatitis B is age-dependent:
- Up to 90 percent of infants
- 30 percent of children ages one to five years
- 2 percent to 6 percent of people over five years of age.
Hepatitis B can be serious for older people and people who already have liver disease. Death is possible, although rare (occurring in about 1 percent of people).
The best
cure for hepatitis B is preventing it in the first place. Prevention is best accomplished with the
hepatitis B vaccine, which is given as a shot. Avoiding high-risk situations can also help prevent infection with the virus.
Statistics on Hepatitis B
Following are some key statistics on this virus:
- The number of new hepatitis B infections per year has declined from an average of 260,000 in the 1980s to about 73,000 in 2003.
- The highest rate of hepatitis B occurs in 20- to 49-year-olds.
- The greatest decline in hepatitis B has occurred among children and adolescents due to routine hepatitis B vaccination.
- About 1.25 million Americans are estimated to be chronically infected with hepatitis B. Of these people, 20 to 30 percent acquired their infection in childhood.
(Click Hepatitis B Statistics for more information.)
