Immunology update: hepatitis B virus immunization today.

Abstract

The concept of adult immunization is difficult for many of the general population and of the physician population alike to perceive as important. In reality, the immunization of pediatric-age patients is largely an accepted fact and ongoing process but adultscanfindmanyreasonstoneglectthemselves. Many physicians are aware that hepatitisB virus (HBV) poses a significant health risk to patients who become infected with this virus. The incidence of HBV infection in the United States is rising despite the availability of effective strategies. Current estimates of the incidence of HBV infection suggest approximately 300 000 new cases annuallyoranincreaseof37%inthelast20years. In the US, adolescents and adults account for the majority of new cases. Over 95% of otherwise healthy adults and older children who acquire HBV recover from the infection and suffer no long-lasting effects. In contrast, children infected undertheageof1yearhavea90%chanceofdeveloping chronic infection and those under 5 years have a 40‐ 50% chance. Children who become infected with HBV are at a disproportionate risk for the development of major complications including chronic hepatitis with cirrhosis and liver failure, fulminant hepatitis and hepatocellular carcinoma. HBV vaccine is truly the first cancer vaccine. During the late 1970s, hepatitis B immune globulin (HBIG) was administered to neonates within the first 2 days of life. This strategy prevented neonatal acquisition of the virus and the administration of HBV vaccine given in combination with HBIG not only prevented infection in infancy but conveyed lasting protection in over 95% of treated infants. The current strategy developed by the Centers for Disease Control (CDC) includes recommendations for universal screening of all pregnant women early in pregnancy and repeated screening of women who are at high risk of HBV infection, i.e. intravenous drug users and those with intercurrent sexually transmitted diseases or clinically evident hepatitis. It is strongly recommended that the first dose of HBV vaccine should be given in the hospital prior to discharge.DatafromTable1indicatethat initial protection is present with just one dose. The recommended hepatitis B vaccine schedule is seen in Table 2. A number of hospitals and health plans have backed away from initiation of HBV vaccination in the newborn nursery. This is a tragic turn of events in the effort to immunize all persons. Each physician must examine his/her own hospital’ s