Should a booster dose be administered in children after mass immunization for hepatitis B?

BACKGROUND: Hepatitis B virus infection is a global health problem and vaccine-preventable disease, but the duration of the effects of HBV vaccination in infants is unknown. OBJECTIVES: The aim of this trial, which comprised children who had received 3 doses as part of the universal HBV immunization program and no additional doses, was to investigate anti-HBs titers and HBsAg status after 9 years. PATIENTS AND METHODS: We performed a descriptive, cross-sectional field research study. The study sample, based on sociodemographics and minimum seroprevalence, was analyzed based on 10.00% ± 1.50 (95% confidence interval) (1150 individuals); trial was realized in a total of 1279 children (623 females and 656 males). Anti-HBs titers were measured by micro-EIA (Dia Sorin-Italy); titers < 10 IU/mL were negative, 10-49 IU/mL were low-positive, and > 50 IU/mL were high-positive. For anti-HBs titers below protective levels, HBsAg was measured by micro-EIA. RESULTS: In approximately half of the children (48.5% in those living in semiurban areas and 42.3% in urban areas), antibody titers were below protective levels. CONCLUSIONS: Mass HBV vaccination, which was implemented in Turkey in 1998, significantly decreases HBsAg positivity in childhood. Nevertheless, it might be necessary to administer a booster dose after 8-9 years in children, especially those in low socioeconomic areas or in whom irregular/insufficient immunization is suspected.