Hepatitis B

Definition

Hepatitis B is a viral infection of the liver caused by the Hepatitis B virus (HBV).

Description

Hepatitis literally refers to any inflammation of the liver. In fact, there are five forms of acute viral Hepatitis that are often clinically indistinguishable from one another. These diseases are unrelated to each other except by the fact that they all cause liver damage.

It is important not to confuse Hepatitis B with any other viral Hepatitis. Each has its own mode of transmission and associated risk factors. Hepatitis A, for example, is transmitted by the fecal-oral route, whereas Hepatitis B is often transmitted through sexual contact or IV drug abuse.

HBV is a known threat to health care workers. Each year in the U.S., an estimated 12,000 health care workers contact Hepatitis B from their patients.

Actually, about 300 people die of the illness or its long-term consequences. To date, only seven health care workers have developed AIDS as a result of occupational exposure. The ease of the transmission of the virus is one of the many challenges facing public health professionals.

Hepatitis B infection may result in a range of health outcomes. After a two- to six-month incubation period, HBV can lead to acute Hepatitis. Most individuals are able to recover completely from an acute infection. However, if the body is unable to mount an effective immune response, a patient may become a "chronic carrier" of Hepatitis B virus.

Chronic carriers are at increased risk of developing cirrhosis of the liver and hepatocellular carcinoma (HCC), a serious liver cancer. In fact, HBV is regarded by many scientists to be second only to tobacco as a known human carcinogen. CDC estimates that approximately 25 percent of carriers suffer chronic symptoms, and those people are at the greatest risk of cirrhosis.

All carriers, whether or not they have active symptoms, have a 12 to 300 times greater risk of developing primary liver cancer than non-carriers.

Causes and Risk Factors

Hepatitis B follows a similar mode of transmission as the human immunodeficiency virus (HIV), the agent responsible for AIDS. Both are transmitted through exposure to infected blood or blood products, sexual contact and from mothers to infants primarily at birth.

However, Hepatitis B appears to be far more infectious than HIV. According to the Centers for Disease Control and Prevention, approximately 30 to 40 percent of acute HBV infections in the U.S. occur in individuals with no known risk factors. In comparison, only 4 percent of AIDS cases have occurred in individuals with no known risk factors.

Hepatitis B is threatening for a variety of other reasons. In addition to the ways in which HIV is spread, Hepatitis B appears to be spread by casual contact. It can be acquired by close contact within families, or from person to person through contact with open skin lesions. The virus may possibly be spread by exposure of mucous membranes to saliva.

Another important fact is that Hepatitis B can remain stable outside the body for days or weeks, even when dry.

Symptoms

Symptoms and signs of Hepatitis B can range from none to minimal in the early stages of the illness, to jaundice (yellowing of the skin), nausea, abdominal pain, fever, and malaise in the acute phase.

After the initial infection, carriers of Hepatitis B usually have few symptoms.

Diagnosis

Diagnosis of Hepatitis B is based upon examination of the blood for characteristic antigens and antibodies associated with the disease.

Treatment

Treatment of Hepatitis B is generally only symptomatic in nature. There are no antiviral agents known to be effective against this infection.

Prevention

Current public health efforts to prevent the disease have focused on vaccinating people in high-risk groups and, increasingly, vaccinating all children and adolescents.

Those at greatest risk are: intravenous drug abusers; heterosexuals with multiple partners; homosexual men; health care workers; and children born to immigrants from China, Southeast Asia, and other areas where Hepatitis B is very common.

In the absence of a cure, only the symptoms can be relieved. The best solution lies in prevention. Two companies have a Hepatitis B vaccine license or use in the U.S. and both are produced by recombinant DNA technology.

Three doses of vaccine are required to achieve effective immunization and will induce adequate antibody in 80 to 95 percent of persons who get three doses. The vaccination schedule most often used is 3 intramuscular injections, with the second and third doses administered at 1 to 6 months after the first.

Adults and older children should receive the injections in the deltoid. Infants should receive the injections in the thigh. Buttock injection should never be used.

As part of a national effort to eliminate Hepatitis B transmission, the Advisory Committee on Immunization Practices, with the concurrence of the American Academy of Pediatrics and the American Academy of Family Physicians, has recommended that all infants receive Hepatitis B vaccine as part of their childhood immunization schedule. This has now become standard practice with some state health departments (e.g., California) now adding immunization against Hepatitis B to required immunizations for children attending public schools.

The previous strategy for preventing Hepatitis B emphasized immunization of selected adults with identified risk factors. This strategy has failed to have an impact on the prevention of Hepatitis B.

The first dose of Hepatitis B vaccine is given soon after birth before the infant is discharged from the hospital or in the first two months of life. The second dose is given between 1 and 2 months after the first and the third at 6 to 18 months of age.

Infants born to mothers infected with Hepatitis B virus should be treated with Hepatitis B immune globulin and Hepatitis B vaccine within 12 hours of birth, with the second and third doses of vaccine given at 1 and 6 months of age.

Questions to Ask Your Doctor

Who is at risk of contracting Hepatitis B?

What treatment is available for Hepatitis B?

Is cirrhosis of the liver or liver cancer likely to develop?

What preventive measures can be taken?

What if I become pregnant?