The researchers tested antibody persistence against hepatitis B virus (HBV) in adolescents who had previously received a hexavalent diphtheria-tetanus-acellular pertussis-HBV-inactivated poliovirus-Haemophilus influenza type b conjugate vaccination as part of Germany’s national neonatal immunization program. The anamnestic response to a challenge dose of a monovalent HBV vaccination was also evaluated. In this phase 4, open-label, non-randomized research (NCT02798952), 302 adolescents aged 14–15, who had been primed with four DTPa-HBV-IPV/Hib doses in their first two years of life received one challenge dose of monovalent HBV vaccination. Blood samples were collected before and one month after immunization to assess antibody levels against the hepatitis B surface antigen (HBs). Reactogenicity and safety were also evaluated following the challenge dosage. Before the challenge dosage, 53.7% of the 268 people in the protocol-compliant group for immunogenicity had anti-HBs antibody concentrations of greater than or equal to 10 mIU/mL (seroprotection cut-off) and 16.8% had anti-HBs antibody concentrations of greater than or equal to 100 mIU/mL. Anti-HBs antibody concentrations greater than or equal to 10 mIU/mL were found in 93.3% of adolescents one month after the challenge dose, and 87.3% had antibody concentrations greater than or equal to 100 mIU/mL. In 92.5% of teenagers, an anamnestic reaction was elicited.

The most often reported local and overall effects were injection site discomfort (in 33.6% of participants) and weariness (30.2%), respectively. Six of the 55 uninvited adverse events recorded were thought to be connected to immunization. During the trial, two significant adverse events unrelated to immunization were recorded. Long-term antibody persistence against hepatitis B was seen in 14–15-year-old adolescents who had previously been primed with DTPa-HBV-IPV/Hib in infancy. A challenging dose of monovalent HBV vaccination elicited a robust anamnestic reaction while posing no safety concerns.

Reference:www.tandfonline.com/doi/full/10.1080/21645515.2018.1509658

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