CausesBy Mayo Clinic Staff
Hepatitis B infection is caused by the hepatitis B virus (HBV). The virus is passed from person to person through blood, semen or other body fluids.
Common ways HBV is transmitted include:
- Sexual contact. You may become infected if you have unprotected sex with an infected partner whose blood, saliva, semen or vaginal secretions enter your body.
- Sharing of needles. HBV is easily transmitted through needles and syringes contaminated with infected blood. Sharing intravenous (IV) drug paraphernalia puts you at high risk of hepatitis B.
- Accidental needle sticks. Hepatitis B is a concern for health care workers and anyone else who comes in contact with human blood.
- Mother to child. Pregnant women infected with HBV can pass the virus to their babies during childbirth. However, the newborn can be vaccinated to avoid getting infected in almost all cases. Talk to your doctor about being tested for hepatitis B if you are pregnant or want to become pregnant.
Acute vs. chronic hepatitis B
Hepatitis B infection may be either short-lived (acute) or long lasting (chronic).
Aug. 29, 2014
- Acute hepatitis B infection lasts less than six months. Your immune system likely can clear acute hepatitis B from your body, and you should recover completely within a few months. Most people who acquire hepatitis B as adults have an acute infection, but it can lead to chronic infection.
Chronic hepatitis B infection lasts six months or longer. When your immune system can't fight off the acute infection, hepatitis B infection may last a lifetime, possibly leading to serious illnesses such as cirrhosis and liver cancer.
The younger you are when you get hepatitis B — particularly newborns or children younger than 5 — the higher your risk the infection becoming chronic. Chronic infection may go undetected for decades until a person becomes seriously ill from liver disease.
- Lok ASF. Clinical manifestations and natural history of hepatitis B virus infection. http://www.uptodate.com/home. Accessed July 11, 2014.
- Lok ASF. Diagnosis of hepatitis B virus infection. http://www.uptodate.com/home. Accessed July 11, 2014.
- Patient information: Hepatitis B (the basics). http://www.uptodate.com/home. Accessed July 15, 2014.
- Hepatitis B FAQs for the public. Centers for Disease Control and Prevention. http://www.cdc.gov/hepatitis/B/bFAQ.htm. Accessed July 11, 2014.
- Hepatitis B. World Health Organization. http://www.who.int/mediacentre/factsheets/fs204/en/#. Accessed July 11, 2014.
- Lok ASF. Overview of management of hepatitis B and case examples. http://www.uptodate.com/home. Accessed July 15, 2014.
- Wang XY, et al. Emerging antivirals for treatment of hepatitis B. World Journal of Gastroenterology. 2014;20:1777.