Antibody level and immunity against Hepatitis B virus infection among general dental practitioners

Abstract

Introduction. Immunization against Hepatitis B virus (HBV) is crucial for an effective control in dental healthcare settings. Nevertheless, vaccination rates among general dental practitioners (GDPs) from developed countries range between roughly 50%, as in Italy and Japan, and >90% as in US and UK. Furthermore, vaccination does not necessarily imply immunity, as serum anti-HBs antigen (Ag) level tends to decrease and booster doses are periodically required. Aim. To investigate HBV vaccination and immunity rates among Italian GDPs. Material and methods. 195 GDPs voluntarily participated. They provided information regarding HBV vaccination in the last 10 years and underwent blood samples to detect serum anti-HBs Ag level. Immune subjects were considered subjects with anti-HBs Ag ≥10 mIU/mL. Vaccination and immunity rates were assessed with 95% confidence intervals (95CIs). Sensitivity (proportion of immune GDPs among vaccinated GDPs), Specificity (proportion non-immune GDPs among non-vaccinated GDPs) also were assessed. Results. 88% GDPs were vaccinated (95CI, 83-92%), but only 83% were immune (95CI, 77-88%). Sensitivity was 95.6%, suggesting that among immune GDPs, 4.4% were not recently vaccinated. Specificity was 50%, suggesting that among nonimmune GDPs, 50% were recently vaccinated. Conclusion. Vaccination rate among Italian GDPs was high. Nevertheless, a fraction of 5% of them was vaccinated but was not immune, thus suggesting that serum antibody level should be periodically checked because susceptible GDPs are at risk for HBV infection.