Hepatitis B
Viral hepatitis affecting the liver, preventable by vaccine.
Hepatitis B is a liver infection caused by the hepatitis B virus (HBV), one of five main hepatitis viruses (A, B, C, D, and E). It can be either acute or chronic. Many people exposed to the virus show no symptoms. When symptoms do appear, they typically start 30 to 180 days after exposure and may include sudden nausea, vomiting, yellowing of the skin and urine, fatigue, and abdominal pain. Acute symptoms usually last a few weeks, though some people feel ill for up to six months. Death from acute HBV is rare. An infection lasting longer than six months is considered chronic. The risk of developing chronic hepatitis B is much higher for those infected at a younger age: about 90% of infants infected around birth become chronic carriers, while fewer than 10% of those infected after age five do. Most people with chronic HBV have no symptoms, but about 25% eventually develop cirrhosis or liver cancer.
The virus spreads through contact with infected blood or body fluids. In regions where hepatitis B is common, most infections occur around birth or from contact with other children’s blood. In areas where it is rare, the main routes are intravenous drug use and sexual intercourse. Other risk factors include healthcare work, blood transfusions, dialysis, living with an infected person, travel to high-prevalence countries, and living in group settings. Tattooing and acupuncture caused many cases in the 1980s, but improved sterilization has made this less common. HBV cannot be spread by holding hands, sharing utensils, kissing, hugging, coughing, sneezing, or breastfeeding. Diagnosis is possible 30 to 60 days after exposure, usually confirmed by blood tests for viral components and antibodies. Initial treatment focuses on symptoms. For chronic cases, antiviral drugs like tenofovir or interferon may help, but they are expensive. Liver transplantation is sometimes needed for cirrhosis or liver cancer.
A vaccine has been available since 1982 and, as of 2022, is 98% to 100% effective. It requires several doses: an initial shot followed by two or three more for full protection. The World Health Organization recommends giving infants the first dose within 24 hours of birth. By the end of 2021, 190 countries had national programs offering the vaccine to infants.
Quick Facts
- Field
- Infectious disease, gastroenterology
- Symptoms
- None, yellowish skin, tiredness, dark urine, abdominal pain
- Complications
- Cirrhosis, liver cancer
- Onset
- Symptoms may take up to 6 months to appear
- Duration
- Short or long term
- Causes
- Hepatitis B virus spread by some body fluids
- Risks
- Intravenous drug use, sexual intercourse, dialysis, living with an infected person
- Diagnosis
- Blood tests
- Prevention
- Hepatitis B vaccine
- Treatment
- Antiviral medication (tenofovir, interferon), liver transplantation
- Frequency
- 296 million (2019)
- Deaths
- 820,000 resulting from hepatitis B (2019)
Facts from the source article.
Lore & Background
Hepatitis B was originally known as 'serum hepatitis'. The virus is transmitted by exposure to infectious blood or body fluids. In areas where the disease is common, infection around the time of birth or from contact with other people's blood during childhood are the most frequent methods of acquisition. In areas where the disease is rare, intravenous drug use and sexual intercourse are the most frequent routes. Other risk factors include working in healthcare, blood transfusions, dialysis, living with an infected person, travel in countries with high infection rates, and living in group living situations. Tattooing and acupuncture led to a significant number of cases in the 1980s, but this has become less common with improved sterilization. The hepatitis B viruses cannot be spread by holding hands, sharing eating utensils, kissing, hugging, coughing, sneezing, or breastfeeding.
Reader's Guide
Hepatitis B is a significant global health concern, with an estimated 296 million people having chronic infections as of 2019 and 820,000 deaths occurring that year due to HBV. The disease is most prevalent in Africa and the Western Pacific region. Chronic infection can lead to cirrhosis and liver cancer in about 25% of those affected. The availability of a highly effective vaccine since 1982 has been a major public health achievement, with national programs making it available for infants in 190 countries by the end of 2021. The World Health Organization recommends infants receive the vaccine within 24 hours after birth when possible. In 2016, the WHO set a goal of eliminating viral hepatitis as a threat to global public health by 2030, which would require developing therapeutic treatments to cure chronic hepatitis B, as well as preventing transmission and using vaccines to prevent new infections. Antiviral medications such as tenofovir or interferon may be useful for chronic cases, though they are expensive.
Did You Know?
- Hepatitis B is 50 to 100 times more infectious than human immunodeficiency virus (HIV).
- About 90% of those infected during or shortly after birth develop chronic hepatitis B.
- The hepatitis B vaccine has been available since 1982 and is between 98% and 100% effective.
- Cirrhosis and liver cancer are responsible for most HBV-related deaths.
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