ABSTRACT
The purpose of this study was to evaluate the long term maintenance of antibody levels in adult healthcare workers and in children [with or without diabetes] after a three-dose regimen of HB vaccine and the ability to boost antibody levels with re-immunization. This study was conducted on 131 individuals including: an Adult group [67] comprising 52 HB vaccinated adult health care workers and 15 unvaccinated adult heath care workers as a control group; and a Children group [64] of 44 non-diabetic and 20 diabetic children. Following proper history and clinical examination, all serum specimens were tested for HBsAg, anti-HBs, anti-HBc and HCV antibodies. The longer the time lapse since the last dose of HB vaccine in both adult health care workers and non-diabetic children, the lower the seroprotection rate [lower mean Anti-HBs levels] [P = 0.006, 0.004 respectively]. Significantly increased Anti-HBs levels were found after booster dose vaccination of either children or adult health care workers [all P < 0.001 for both] and 97.22% of serongative children; 100% of the seronegative adults turned seropositive. HB vaccine could be highly protective against HBV infection as evidenced by the absence of hepatitis B infection in the vaccinated groups. The longer the time lapse after vaccination, the lower is the seroprotection rate and the lower the mean Anti-HBs, but with persistence of an effective immunological memory in vaccinees. HB vaccine boosting could be advised for high risk subjects including adult health care workers and diabetic children at five year intervals