HEPATITIS-B VACCINE - CURRENT ISSUES

OBJECTIVE: To review two main issues concerning the hepatitis B vaccin e: (1) the management of unresponsive subjects and (2) the need for ro utine booster doses. DATA SOURCES: Pertinent literature identified via MEDLINE (1980-1996) search as well as references cited in published a rticles. DATA SYNTHESIS: The optimal procedure for management of subje cts unresponsive to hepatitis B vaccine has not been well established. Most unresponsive subjects are not absolute nonresponders, since most of them can develop protective concentrations of antibodies to hepati tis B surface antigen (anti-HBsAg) after hepatitis B revaccination, co nsisting of a fourth or a fifth dose or a new complete course of immun ization. In subjects who do not respond to the hepatitis B vaccine aft er four or more injections, the benefits of the combination of cytokin es (e.g., interferon-alfa, interleukin-2 [aldesleukin]) and vaccine ha ve not been clearly shown. There are two main opinions regarding the n eed for routine booster doses. Experts from the US, claiming long-term protection from immunologic memory, suggest delaying booster doses fo r at least a decade after vaccination in subjects with normal immune s tatus. Furthermore, postvaccination antibody testing should be restric ted only to high-risk subjects. Once a vaccinated subject has responde d satisfactorily, further antibody tests are unnecessary. Only hemodia lysis patients should be tested annually for adequate antibody concent rations and the booster dose administered when concentrations decline to less than 10 IU/L. Experts from Europe suggest that vaccine-induced antibody responses should be assessed in all subjects and booster dos es administered at intervals, with the theory being that protection co rrelates with the presence of antibody. However, indications about app ropriate timing for booster doses and target titers of anti-HBsAg rema in controversial. CONCLUSIONS: It is possible to obtain seroconversion in nonresponders by using variations in vaccination strategies (i.e., >3 doses, double amounts of HBsAg). Adjuvants such as interferon-alfa or aldesleukin are of limited use. The opinions of American experts r egarding routine booster doses, as expressed by the statement of the I mmunization Practices Advisory Committee, seem to be well defined and helpful to clinicians trying to resolve controversies for individual p atients. The opinions of the European experts are not unanimous and ar e sometimes impractical. A consensus conference is needed.