Hepatitis B (cont.)

New agents are under development to treat hepatitis B. Many of these are nucleoside/nucleotide analogues that investigators hope will be more effective than older agents. Experts also are working on treatment guidelines and the use of multi-drug therapy. Vaccination remains the key to preventing hepatitis B and holds the most promise for reducing disease burden.

• The hepatitis B virus is a DNA virus belonging to the Hepadnaviridae family of viruses. Hepatitis B virus is not related to the hepatitis A virus or the hepatitis C virus.
  
  
• Some people with hepatitis B never clear the virus and are chronically infected. Approximately 350 million individuals in the world and one million in the United States are chronically infected with hepatitis B. Many of these people appear healthy but can spread the virus to others.
  
  
• Hepatitis B infection is transmitted through sexual contact, contact with contaminated blood (for example, through shared needles used for illicit, intravenous drugs), and from mother to child. Hepatitis B is not spread through food, water, or casual contact.
  
  
• Serologic (blood) markers specifically for hepatitis B virus are used to diagnose hepatitis B viral infection. The blood tests can also identify people who are at highest risk for complications.
  
  
• Injury to the liver by hepatitis B virus is caused by the body's immune response as the body attempts to eliminate the virus.
  
  
• In the United States, 95% of adults who get hepatitis B are able to clear the virus and cure themselves of infection. The remaining 5% of adults with acute hepatitis B go on to develop chronic hepatitis B. Those who acquire the infection in childhood are much more likely to have chronic infection. Chronic hepatitis B may lead to cirrhosis or liver failure. Approximately 15% to 25% of persons with chronic infection will die prematurely as a result of the infection.
  
  
• Progression of chronic hepatitis B viral infection occurs insidiously (subtly and gradually), usually over several decades. The course is determined primarily by the age at which the hepatitis B viral infection is acquired and the interaction between the virus and the body's immune system.
  
  
• Treatment with interferons or nucleoside/nucleotide analogues suppresses viral reproduction in about 40% to 90% of patients with chronic hepatitis B. The medications are also effective in reducing inflammation and improving blood tests. This can delay or reduce complications such as cirrhosis. However, most people do not have a permanent response and relapse is common. The medications do not cure the infection.
  
  
• Liver transplantation should be considered for patients with impending liver failure due to acute (initial) infection or advanced cirrhosis.
  
  
• Hepatitis B is preventable through vaccination. All children should receive the vaccine. In addition, adults at high risk for hepatitis B should be vaccinated. Unvaccinated people who are exposed to hepatitis B should be evaluated by a physician to determine if they need specific immune globulin (HBIG).

Reference: Centers for Disease Control and Prevention, "Viral Hepatitis FAQs for the Public," January 15, 2009

Previous contributing medical author and editor: Tse-Ling Fong, MD and Leslie J. Schoenfield, M.D., Ph.D.

Last Editorial Review: 3/24/2009

Source: MedicineNet.com
http://www.medicinenet.com/hepatitis_b/article.htm