Immunity to hepatitis B persists in adolescents 15–16 years of age vaccinated in infancy with three doses of hepatitis B vaccine

AbstractObjectiveVaccination of infants against hepatitis B virus (HBV) using hepatitis B vaccine is effective in preventing the infection during early childhood and there is a growing evidence of long-term protection. So far, no need for a booster dose has been identified in healthy subjects; however further follow-up continues to determine the exact duration of protection. We evaluated antibody persistence and immune response to a hepatitis B vaccine challenge dose in children aged 15–16 years, previously vaccinated with 3-doses of the same vaccine in infancy (third dose received before 18 months of age).MethodsA single hepatitis B vaccine challenge dose containing 10μg hepatitis B surface (HBs) antigen was administered to adolescents aged 15–16 years. Blood samples were taken before and one month after the challenge dose to measure anti-HBs antibodies using a chemiluminescence immunoassay. Solicited local and general symptoms, as well as unsolicited and serious adverse events were recorded after the challenge dose.Results303 subjects were enrolled, of whom 302 and 293 subjects formed the total vaccinated and according-to-protocol cohorts, respectively. Pre-challenge, 65.4% (95% CI: 59.6–70.9) subjects were seroprotected (anti-HBs antibody concentration ≥10mIU/mL). One month post-challenge, 97.9% (95% CI: 95.6–99.2) were seroprotected, while 90.8% (95% CI: 86.8–93.8) had anti-HBs antibody concentrations ≥100mIU/mL. The post-challenge geometric mean concentration (GMC; 4134.9 [95% CI: 3114.2–5490.1]) was 150-fold higher than the pre-challenge GMC. Overall, 96.9% (95% CI: 94.2–98.6) subjects mounted an anamnestic response. The safety and reactogenicity profile of the hepatitis B vaccine challenge dose was consistent with previous experience.ConclusionsImmunity to hepatitis B persists in 15–16 year old adolescents following primary vaccination in infancy.Trial registrationhttp://www.clinicaltrials.gov NCT01847430