THE NEED FOR POSTVACCINATION SEROLOGY AND THE TIMING OF BOOSTER VACCINATIONS AGAINST HEPATITIS-B IN DENTAL-HEALTH CARE WORKERS

Viral hepatitis caused by the hepatitis B virus is a disease which has no oral manifestations but is of direct concern to dental health care workers due to its transmissibility by transfer of minute quantities of infected body fluids from patients with the condition. Many chronic carriers of HBV do not have signs and symptoms of hepatitis and are frequently unaware of the virus they harbour. In recent years immunization against HBV has become possible and a high success rate has been achieved in inducing immunity against HBV in dental health care workers who have completed an immunization programme. When the HBV vaccines were introduced to widespread clinical use in the 1980s it was optimistically predicted that immunity conferred by the vaccines would be for ten years. Recent research has cast severe doubts on this optimism and clinical trials have indicated that the immunity may be short-lived and varies between individuals. Longevity of immunity is dependent upon antibody levels attained by the immunization programme. Post-immunization antibody levels can be utilized as a guide to the longevity of the immunity and hence should serve as a prognostic indicator for timing of booster inoculations.