Epidemiology of Hepatitis B
المؤلف:
Mary Louise Turgeon
المصدر:
Immunology & Serology in Laboratory Medicine
الجزء والصفحة:
5th E, P292-293
2025-08-30
293
Hepatitis B infection has been referred to as long-incubation hepatitis. In 2009 (the last year for which statistics were available at the time of publication), a total of 3371 acute symptomatic cases and 38,000 estimated total new infections of hepatitis B were reported in the United States. The overall incidence was the lowest ever recorded and represents a decline of 81% since 1990 (Fig. 1).
Fig1. Incidence of hepatitis B, by year, 1982-2009. (Courtesy National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta.)
About 1.25 million people in the United States have chronic HBV infection, 20% to 30% of whom acquired the infection in childhood. Each year, about 3000 to 5000 people die from cirrhosis or liver cancer caused by HBV. The highest rate of dis ease occurs in those ages 20 to 49 years. The greatest decline has occurred in children and adolescents as a result of routine hepatitis B vaccination.
The incidence of HBV infection caused by blood transfusion is increasingly rare in developed countries. Transfusion acquired HBV has been severely reduced because high-risk donor groups (e.g., paid donors, prison inmates, military recruits) have been eliminated as major sources of donated blood and because specific serologic screening procedures have been instituted. This shift to an all-volunteer donor supply probably accounts for a 50% to 60% reduction of transfusion related hepatitis. The overall incidence of HBV is high among patients who have received multiple transfusions or blood components prepared from multiple-donor plasma pools, hemodialysis patients, drug addicts, and medical personnel ( Table 1).
Table1. Characteristics of Viral Hepatitis
Persons at risk of exposure to HBV, including those mentioned earlier, include members of the following groups:
• Heterosexual men and women
• Homosexual men with multiple partners
• Household contacts and sexual partners of HBV carriers
• Infants born to HBV-infected mothers
• Patients and staff in custodial institutions for develop mentally disabled persons
• Recipients of certain plasma-derived products, including patients with congenital coagulation defects
• Health care and public safety workers who may be in contact with infected blood
• Persons born in HBV-endemic areas and their children
Hepatitis B virus does not seem capable of penetrating the skin or mucous membranes; therefore, some break in these barriers is required for disease transmission. Transmission of HBV occurs via percutaneous or permucosal routes and infective blood or body fluids can be introduced at birth, through sexual contact, or by contaminated needles. Infection can also occur in settings of continuous close personal contact. About 50% of patients with acute type B hepatitis have a history of parenteral exposure. Inapparent parenteral exposure involves intimate or sexual contact with an infectious individual. Transmission between siblings and other household contacts readily occurs via transmission from skin lesions such as eczema or impetigo, sharing of potentially blood-contaminated objects such as toothbrushes and razor blades, and occasionally through bites. HBV has been found in saliva, semen, breast milk, tears, sweat, and other biological fluids of HBV carriers. Urine and wound exudate are capable of harboring HBV. Stool is not considered to be infectious.
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