Hepatitis B

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Q

What is hepatitis B?
How is it transmitted?
What illnesses does the virus cause?
What are the symptoms?
How long does it take for symptoms to occur?
How do I know if I have hepatitis B?
How long does it take for a blood test to detect the virus?
How is it treated?
How effective is the vaccine?
Why screen donated blood for hepatitis B?


A

What is hepatitis B?

Hepatitis B is caused by a virus that attacks the liver. The hepatitis B virus can cause lifelong infection, cirrhosis (scarring) of the liver, liver cancer, liver failure and death.1

A

How is it transmitted?

The hepatitis B virus is transmitted by contact with blood or body fluids of an infected person.

  • Developing countries:2 Most infections occur from infected mother to child, from child-to-child contact in household settings and from reuse of unsterilized needles and syringes. In many developing countries, almost all children become infected with the virus.
  • Industrialized countries:2 Mother-to-infant and child-to-child transmission has dropped substantially, thanks to childhood hepatitis B vaccination programs. Primary means of transmission in these countries is through sexual activity and injected drug use. In addition, hepatitis B virus is the major infectious occupational hazard of health workers, and most health care workers have received hepatitis B vaccine.
The hepatitis B virus is not spread by contaminated food or water, and cannot be spread casually in the workplace.2

A

What illnesses does the virus cause?

The hepatitis B virus attacks the liver, causing lifelong infection, cirrhosis (scarring) of the liver, liver cancer, liver failure and death.1

A

What are the symptoms?

A person with hepatitis B infection may or may not have symptoms. Symptoms occur in about 70 percent of patients and are more likely to occur in adults than in children. Symptoms may include:1

  • Yellow skin or yellowing of the whites of your eyes (jaundice)
  • Tiredness
  • Loss of appetite
  • Nausea
  • Abdominal discomfort
  • Dark urine
  • Clay-colored bowel movements
  • Joint pain

A

How long does it take for symptoms to occur?

If symptoms occur, they occur on the average of 12 weeks (range 9-21 weeks) after exposure to the hepatitis B virus.1

A

How do I know if I have hepatitis B?

A blood test is the only way to know for sure.1 Blood is tested for the presence of specific anti-viral antigens or antibodies.2

A

How long does it take for a blood test to detect the virus?

The hepatitis B surface antigen, HbsAg, will be detected in an infected person's blood on the average of 4 weeks (range 1-9 weeks) after exposure to the virus. About one out of two patients will no longer be infectious by seven weeks after onset of symptoms. Patients who do not remain chronically infected will be HBsAg-negative by 15 weeks after onset of symptoms.1

A

How is it treated?

There is no specific treatment for acute viral hepatitis B. Chronic hepatitis B may be treated with antiviral drugs.1,2 However, many of those infected in developing countries do not have access to these drugs.

Patients with cirrhosis are sometimes given liver transplants, with varying success. It is preferable to prevent this disease with vaccine than to try and cure it.2

A

How effective is the vaccine?

Hepatitis B is preventable with safe, effective vaccines that have been available since 1982. If the vaccine is administered before infection, it prevents the development of the disease and the carrier state in almost all individuals. It has been given to more than 500 million persons and has proved one of the safest, most immunogenic and effective vaccines.2

A

Why screen donated blood for hepatitis B?

Because the hepatitis B virus is transmitted by contact with blood, it can be transmitted through blood transfusions. Blood donors could be infected with hepatitis B without knowing it, because:

  • Hepatitis B often does not have symptoms in 30 percent of patients1
  • It can take an average of 12 weeks (range 9-21 weeks) after exposure to the hepatitis B virus to experience symptoms1

Blood donation screening for the hepatitis B surface antigen, HBsAg, was mandated in the US. in 1972. The introduction of screening for the antibody to the hepatitis B surface antigen, anti-HBc, in the US. in 1986 has efficiently excluded those donors who were persistent, low-level carriers, and those in the window period of acute infection.2

in the US., the current overall risk of acquiring hepatitis B after a transfusion is about one in 50,000 per recipient. However, donors who are in the early incubation stage of their disease, capable of transmitting hepatitis B, remain unidentified with current techniques.2

 

References

  1. Centers for Disease Control and Prevention Website - Viral hepatitis B page. Accessed Aug. 5, 2005.
  2. World Health Organization - Hepatitis B page. Accessed Aug. 5, 2005.
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